SCS 185_Manual 185 Manual

User Manual: SCS-185_Manual

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Project 47

-1-

Most circuit problems are due to incorrect assembly, always

double-check that your circuit exactly matches the drawing for it.

2. Be sure that parts with positive/negative markings are

positioned as per the drawing.

3. Be sure that all connections are securely snapped.

4. Try replacing the batteries.

5. If the flexible sheet in the sound energy demo container is

damaged, replace it with a spare (if one was included), or use

household plastic wrap.

6. If the echo IC (U28) stops working, turn the circuit off and on

to reset it.

ELENCO®is not responsible for parts damaged due to incorrect wiring.

Basic Troubleshooting

Note: If you suspect you have damaged parts, you can follow the

Advanced Troubleshooting procedure on pages 16 and 17 to determine

which ones need replacing.

Basic Troubleshooting 1

Parts List 2, 3

How to Use Snap Circuits® 4

About Your Snap Circuits®SOUND Parts 5-7

Introduction to Electricity 8

Sound in Our World 9-14

DO’s and DON’Ts of Building Circuits 15

Advanced Troubleshooting 16, 17

Project Listings 18, 19

Projects 1 - 188 20-85

Other Snap Circuits®Projects 86

WARNING: SHOCK HAZARD - Never connect Snap

Circuits®to the electrical outlets in your home in any way!

Table of Contents

WARNING: Always check your wiring

before turning on a circuit. Never leave

a circuit unattended while the batteries

are installed. Never connect additional

batteries or any other power sources to

your circuits. Discard any cracked or

broken parts.

Adult Supervision: Because children’s

abilities vary so much, even with age

groups, adults should exercise

discretion as to which experiments are

suitable and safe (the instructions

should enable supervising adults to

establish the experiment’s suitability for

the child). Make sure your child reads

and follows all of the relevant

instructions and safety procedures, and

keeps them at hand for reference.

This product is intended for use by

adults and children who have attained

sufficient maturity to read and follow

directions and warnings.

Never modify your parts, as doing so

may disable important safety features in

them, and could put your child at risk of

injury.

WARNING: CHOKING HAZARD -

Small parts. Not for children under 3 years.

Conforms to all applicable

U.S. government

requirements.

• Use only 1.5V “AA” type, alkaline batteries

(not included).

• Insert batteries with correct polarity.

•

Non-rechargeable batteries should not be

recharged. Rechargeable batteries should

only be charged under adult supervision, and

should not be recharged while in the product.

• Do not mix old and new batteries.

• Do not connect batteries or battery holders

in parallel.

• Do not mix alkaline, standard (carbon-

zinc), or rechargeable (nickel-cadmium)

batteries.

• Remove batteries when they are used up.

• Do not short circuit the battery terminals.

• Never throw batteries in a fire or attempt to

open its outer casing.

• Batteries are harmful if swallowed, so keep

away from small children.

Batteries:

WARNING: Some projects are intended for use with

headphones (not included in this set). Headphones

performance varies, so you should use caution.

Permanent hearing loss may result from long-term

exposure to sound at high volumes. Start with as

low a volume as possible, then carefully increase to

a comfortable level. Ringing or discomfort in the

ears may indicate that the sound levels are too high;

immediately discontinue using the headphones with

this product and consult a physician.

-2-

Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER. Call toll-free (800) 533-2441 or e-mail us at:

help@elenco.com. Customer Service • 150 Carpenter Ave. • Wheeling, IL 60090 U.S.A.

Parts List (Colors and styles may vary) Symbols and Numbers (page 1)

Qty. ID Name Symbol Part # Qty. ID Name Symbol Part #

r1Base Grid

(11.0” x 7.7”) 6SCBG r10.1mF Capacitor 6SCC2

r31-Snap Wire 6SC01 r1470mF Capacitor 6SCC5

r72-Snap Wire 6SC02 r11mF Capacitor 6SCC7

r33-Snap Wire 6SC03 r1Color Light Emitting

Diode (LED) 6SCD8

r14-Snap Wire 6SC04 r1Egg LED Attachment 6SCEGG

r15-Snap Wire 6SC05 r1Jumper Wire (black) 6SCJ1

r16-Snap Wire 6SC06 r1Jumper Wire (red) 6SCJ2

Battery Holder - uses

two (2) 1.5V type “AA”

(not included)

6SCB1 r1Audio Jack 6SCJA

You may order additional / replacement parts at our website: www.snapcircuits.net

B1 JA

-3-

Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER. Call toll-free (800) 533-2441 or e-mail us at:

help@elenco.com. Customer Service • 150 Carpenter Ave. • Wheeling, IL 60090 U.S.A.

Parts List (Colors and styles may vary) Symbols and Numbers (page 2)

Qty. ID Name Symbol Part # Qty. ID Name Symbol Part #

r1NPN Transistor 6SCQ2 r1

Tube for Sound

Energy Demo

Container

6SCSEDCT

r1100WResistor 6SCR1 r1

Flexible Sheet for Sound

Energy Demo Container

(may include spare)

6SCSEDCF

r15.1kWResistor 6SCR3 r1Speaker 6SCSP2

r1Adjustable Resistor 6SCRV r1Keyboard 6SCU26

r1500kWAdjustable

Resistor 6SCRV3 r1Voice Changer 6SCU27

r1Photoresistor 6SCRP r1Echo IC 6SCU28

r2Slide Switch 6SCS1 r1Microphone 6SCX1

r1Press Switch 6SCS2 r1Stereo Cable 9TLSCST

Base for Sound

Energy Demo

Container

6SCSEDCB

You may order additional / replacement parts at our website: www.snapcircuits.net

U27

SP2

U28

U26

RV3

How to Use Snap Circuits

Snap Circuits®uses building blocks with snaps

to build the different electrical and electronic

circuits in the projects. Each block has a

function: there are switch blocks, light blocks,

battery blocks, different length wire blocks, etc.

These blocks are different colors and have

numbers on them so that you can easily

identify them. The blocks you will be using are

shown as color symbols with level numbers

next to them, allowing you to easily snap them

together to form a circuit.

For Example:

This is the switch block, which is green and has

the marking on it. The part symbols in this

booklet may not exactly match the appearance

of the actual parts, but will clearly identify them.

This is a wire block, which is blue and comes

in different wire lengths.

This one has the number , , , ,

or on it depending on the length of the wire

connection required.

There is also a 1-snap wire that is used as a

spacer or for interconnection between different

layers.

You need a power source to build each circuit.

This is labeled and requires two (2) 1.5V

“AA” batteries (not included).

A large clear plastic base grid is included with

this kit to help keep the circuit blocks properly

spaced. You will see evenly spaced posts that

the different blocks snap into. The base has

rows labeled A-G and columns labeled 1-10.

Next to each part in every circuit drawing is a

small number in black. This tells you which

level the component is placed at. Place all

parts on level 1first, then all of the parts on

level 2, then all of the parts on level 3, etc.

Some circuits use the jumper wires to make

unusual connections. Just clip them to the

metal snaps or as indicated.

This set contains an egg LED attachment,

which can be mounted on the color LED (D8)

to enhance its light effects.

This set contains a sound energy

demonstration container, which will sometimes

be placed over the speaker. Its use is

explained in project 13.

To assemble it, lay the tube and flexible sheet

over the base, and then push the tube into the

base, as shown. Do not disassemble it except

to repair it. This set may include a spare for the

flexible sheet, and household plastic wrap also

works.

23 4 5

-4-

Egg LED attachment

mounted to D8

Egg

Note: While building the projects, be careful not

to accidentally make a direct connection across

the battery holder (a “short circuit”), as this may

damage and/or quickly drain the batteries.

Sound Energy Demonstration

Container Assembly

(Adult supervision recommended)

Flexible

sheet

Base

Tube

-5-

About Your Snap Circuits®SOUND Parts

(Part designs are subject to change without

notice).

BASE GRID

The blue snap wires

are wires used to

connect components.

They are used to

transport electricity and do

not affect circuit performance.

They come in different lengths to

allow orderly arrangement of connections

on the base grid.

The red and black

jumper wires make

flexible connections for

times when using the snap wires

would be difficult. They also are

used to make connections off the base grid.

Wires transport electricity just like pipes are used

to transport water. The colorful plastic coating

protects them and prevents electricity from

getting in or out.

BATTERY HOLDER

The base grid is a platform for mounting parts

and wires. It functions like the printed circuit

boards used in most electronic products, or like

how the walls are used for mounting the electrical

wiring in your home.

SNAP WIRES & JUMPER WIRES

The batteries (B1) produce an electrical voltage

using a chemical reaction. This “voltage” can be

thought of as electrical pressure, pushing

electricity through a circuit just like a pump

pushes water through pipes. This voltage is

much lower and much safer than that used in

your house wiring. Using more batteries

increases the “pressure”, therefore, more

electricity flows.

Battery Holder (B1)

SLIDE & PRESS SWITCHES

The slide & press switches (S1 & S2) connect

(pressed or “ON”) or disconnect (not pressed or

“OFF”) the wires in a circuit. When ON they have no

effect on circuit performance. Switches turn on

electricity just like a faucet turns on water from a pipe.

Slide & Press

Switches

(S1 & S2)

RESISTORS

Resistors “resist” the flow of electricity and are

used to control or limit the current in a circuit.

Snap Circuits®SOUND includes 100W(R1) and

5.1kW(R3) resistors (“k” symbolizes 1,000, so

R3 is really 5,100W). Materials like metal have

very low resistance (<1W), while materials like

paper, plastic, and air have near-infinite

resistance. Increasing circuit resistance reduces

the flow of electricity.

Resistors (R1 & R3)

Adjustable Resistor (RV)

The adjustable

resistor (RV) is a

50kWresistor but

with a center tap

that can be adjusted

between 200Wand

50kW.

The 500kWadjustable resistor (RV3) is a

500kWresistor that can be adjusted between

200Wand 500kW.

500kWAdjustable Resistor (RV3)

About Your Snap Circuits®SOUND Parts

LED

-6-

The speaker (SP) converts electricity into sound

by making mechanical vibrations. These

vibrations create variations in air pressure, which

travel across the room. You “hear” sound when

your ears feel these air pressure variations.

SPEAKER

Speaker (SP2)

Color LED

(D8)

The color LED (D8) is a light emitting diode, and

may be thought of as a special one-way light

bulb. In the “forward” direction, (indicated by the

“arrow” in the symbol) electricity flows if the

voltage exceeds a turn-on threshold (about 1.5V

for red, about 2.0V for green, and about 3.0V for

blue); brightness then increases. The color LED

contains red, green, and blue LEDs, with a micro-

circuit controlling then. A high current will burn

out an LED, so the current must be limited by

other components in the circuit. LED’s block

electricity in the “reverse” direction.

CAPACITOR

The 0.1mF, 1 mF, and 470mF capacitors (C2, C7,

& C5) can store electrical pressure (voltage) for

periods of time. This storage ability allows them

to block stable voltage signals and pass

changing ones. Capacitors are used for filtering

and delay circuits.

Microphone (X1)

The microphone (X1) is actually a resistor that

changes in value when changes in air pressure

(sounds) apply pressure to its surface.

MICROPHONE

The photoresistor (RP) is a light-sensitive

resistor, its value changes from nearly infinite in

total darkness to about 1000Wwhen a bright light

shines on it.

Photoresistor (RP)

Capacitors (C2, C5, & C7)

TRANSISTORS

ELECTRONIC MODULES

The NPN transistor (Q2) is a component that

uses a small electric current to control a large

current, and is used in switching, amplifier, and

buffering applications. Transistors are easy to

miniaturize, and are the main building blocks of

integrated circuits including the microprocessor

and memory circuits in computers.

The keyboard (U26) contains resistors,

capacitors, switches, and an integrated circuit. It

can produce two adjustable audio tones at the

same time. The tones approximate musical

notes, and may not be exact. The tone of the

green keys can be adjusted with the tune knob

or using external resistors and capacitors. A

schematic for it is available at

www.snapcircuits.net/faq.

Connections:

(+) - power from batteries

RES - resistor freq adjust

CAP - capacitor freq adjust

OUT - output connection

(–) - power return to batteries

See projects 1, 6, & 25 for example of proper connections.

NPN Transistor (Q2)

Keyboard (U26)

-7-

About Your Snap Circuits®SOUND Parts

Audio Jack (JA)

OTHER PARTS The stereo cable is used to connect the

audio jack (JA) to your music device or

external speaker.

The audio jack (JA) is a connector

mounted on snaps, and is used for

interfacing your music device or external

speaker to Snap Circuits®.

The egg LED attachment can be used

with the color LED (D8) to enhance the

light effects.

Egg

The sound energy demonstration

container is used to show that sound

waves have energy, and can move

things around. See project 13.

Connections:

(+) - power from batteries

SPD - speed adjust

SP+ - speaker (+)

SP– - speaker (–)

MIC+ - microphone (+)

MIC– - microphone (–)

REC - record

PLY - play

(–) - power return to batteries

See project 7 for example of

proper connections.

The voice changer (U27) contains resistors, capacitors,

and an integrated circuit that are needed to record and

play back sound at different speeds. A schematic for it is

available at www.snapcircuits.net/faq.

Connections:

(+) - power from batteries

G+ - gain control

G– - gain control

ADJ - echo adjust

INP - input connection

OUT - output connection

(–) - power return to

batteries

See projects 10 & 41 for

examples of proper

connections.

The echo IC (U28) contains resistors, capacitors, and

integrated circuits that are needed to add echo effects to

a sound. A schematic for it is available at

www.snapcircuits.net/faq.

Introduction to Electricity

What is electricity? Nobody really knows. We only know how to produce it,

understand its properties, and how to control it. Electricity is the movement of sub-

atomic charged particles (called electrons) through a material due to electrical

pressure across the material, such as from a battery.

Power sources, such as batteries, push electricity through a circuit, like a pump

pushes water through pipes. Wires carry electricity, like pipes carry water. Devices

like LEDs, motors, and speakers use the energy in electricity to do things. Switches

and transistors control the flow of electricity like valves and faucets control water.

Resistors limit the flow of electricity.

The electrical pressure exerted by a battery or other power source is called

voltage and is measured in volts (V). Notice the “+” and “–” signs on the battery;

these indicate which direction the battery will “pump” the electricity.

The electric current is a measure of how fast electricity is flowing in a wire, just

as the water current describes how fast water is flowing in a pipe. It is expressed

in amperes (A) or milliamps (mA, 1/1,000 of an ampere).

The “power” of electricity is a measure of how fast energy is moving through a

wire. It is a combination of the voltage and current (Power = Voltage x Current). It

is expressed in watts (W).

The resistance of a component or circuit represents how much it resists the

electrical pressure (voltage) and limits the flow of electric current. The relationship

is Voltage = Current x Resistance. When the resistance increases, less current

flows. Resistance is measured in ohms (W), or kilo ohms (kW, 1,000 ohms).

Nearly all of the electricity used in our world is produced at enormous generators

driven by steam or water pressure. Wires are used to efficiently transport this

energy to homes and businesses where it is used. Motors convert the electricity

back into mechanical form to drive machinery and appliances. The most important

aspect of electricity in our society is that it allows energy to be easily transported

over distances.

Note that “distances” includes not just large distances but also tiny distances. Try

to imagine a plumbing structure of the same complexity as the circuitry inside a

portable radio - it would have to be large because we can’t make water pipes so

small. Electricity allows complex designs to be made very small.

There are two ways of arranging parts in a circuit, in series or

in parallel. Here are examples:

Placing components in series increases the resistance; highest

value dominates. Placing components in parallel decreases the

resistance; lower value dominates.

The parts within these series and parallel sub-circuits may be

arranged in different ways without changing what the circuit

does. Large circuits are made of combinations of smaller series

and parallel circuits.

Series Circuit

Parallel Circuit

-8-

Sound in Our World

Sound is a variation in air pressure created by

a mechanical vibration. See projects 13 & 51

for a demonstration of this. These air pressure

variations travel across the room like waves,

so we call them sound waves. You “hear”

sound when your ears feel these air pressure

variations, and convert them to nerve pulses

that your brain interprets. Eventually the

energy of a sound wave is absorbed, and

becomes heat.

Sound waves can also be thought of as waves

of temporary compression that travel through

materials. Notice that at a loud concert you can

sometimes feel the pressure waves, in

addition to hearing them. Sound waves can

travel through liquids and solids but their

speed may change and their energy may be

reduced, depending on the characteristics of

the material. Sound waves can only travel

through a compressible material, and so

cannot travel through a vacuum. Outer space

is silent, because there is no air or other

material for sound waves to travel through.

The “hearing” part of your ear is inside your

skull; the flaps you see are just funnels to

collect the sound and pass it along to your

eardrum inside. When you were young your

brain learned to interpret the difference in the

information collected from your two ears, and

use it to know which direction a sound came

from. If one of your ears is clogged, then it is

difficult to determine a sound’s direction.

You can compare sound waves from your

voice to waves in a pond. When you speak,

the movements in your mouth create sound

waves just as tossing a rock into the pond

creates water waves. Sound waves travel

through air as water waves travel across the

pond. If someone is nearby, then their ears will

feel the air pressure variations caused by your

sound waves just as a small boat at the other

side of the pond will feel the water waves.

If the mechanical vibration causing the sound

wave occurs at a constant rate, then the sound

wave will repeat itself at the same rate; we

refer to this as the frequency of the sound

wave. Nearly all sound waves have their

energy spread unevenly across a range of

frequencies. When you say a word, you create

a sound wave with energy at various

frequencies, just as tossing a handful of

various-sized rocks into the pond will create a

complicated water wave pattern.

Frequency measures how many times

something occurs per second, expressed in

units called hertz (Hz). The metric prefixes can

be used, so 1,000 repetitions per second is 1

kilohertz (kHz) and 1,000,000 repetitions per

second is 1 megahertz (MHz). The range of

frequencies that can be heard by the human

ear is approximately 20 to 20,000 Hz and is

referred to as the audio range.

Just as there are sound waves caused by

mechanical vibrations, there are also electrical

waves caused by electrical variations. Just as

sound waves travel through air, electrical

waves travel through wires. A microphone

senses pressure variations from sound waves

and creates electrical waves at the same

frequencies. A speaker converts electricity into

sound, by using the energy in electrical waves

to create mechanical vibrations (sound waves)

at the same frequencies.

How does the speaker make sound? An

electric current flowing through a wire has a

very, very tiny magnetic field. Inside the

speaker is a coil of wire and a magnet. The coil

of wire concentrates the magnetic field from

the flowing electric current, enough to make

the magnet move slightly, like a vibration. The

magnet’s vibration creates the air pressure

variations that travel to your ears.

Your speaker can only create sound from a

CHANGING electrical signal, for unchanging

electrical signals it acts like a 32 ohm resistor.

(An unchanging signal does not cause the

magnet in the speaker to move, so no sound

waves are created). Electrical variations at

high frequencies (referred to as radio

frequencies) cannot be heard by your ears, but

can be used to create electromagnetic radio

waves, which travel through air and are used

for many forms of communication. In AM and

FM radio, voice or music is superimposed on

radio waves, allowing it to be transmitted over

great distances, to later be decoded and

listened to.

-9-

Sound and water waves

Speaker

sound waves

Sound in Our World

In stereo, sound is produced on several

speakers (or earphones) with varying

frequencies/loudness on each. This gives the

impression that the sound is coming from

different directions, and is more pleasing to

listen to. Mono sound is the same on all

speakers, and is easier to produce. Note that

a “stereo speaker” can be several speakers

(possibly of different sizes) in one package.

Your Snap Circuits®speaker (SP2) is a mono

speaker. Surround sound is a technique for

placing several speakers (with different

sounds from each) around the listener, to

create a more interesting listening experience.

The loudness of sound waves is a measure of

the pressure level, and is expressed in

decibels (dB, a logarithmic scale). Long-term

exposure to loud sounds can lead to hearing

loss. Here are some examples of sound levels:

Sound waves travel very fast, but sometimes

you can perceive the effects of their speed.

Ever notice how sometimes you see lightning

before you hear the thunder? The reason is

because light travels at about 186,000 miles

per second, while sound travels at only about

1,100 feet per second in air. Sound can travel

through liquids and solids, but with increased

speed (the speed depends on the material’s

compressibility and density). Sound travels 4.3

times faster in water than in air; this difference

in speed confuses our ears, making it difficult

to perceive the direction of sound while

underwater.

A sonic boom is a shock wave that occurs

when an object travels through air at

supersonic speeds (faster than the speed of

sound). These sonic shock waves are similar

to how the bow of a boat produces waves in

the water. Sonic shock waves can carry a lot

of sound energy and can be very unpleasant

to hear, like an explosion. Aircraft can fly at

supersonic speeds, and the sonic boom

produced is so unpleasant that aircraft are

rarely permitted to fly at supersonic speeds

over populated areas.

Sound waves can reflect off walls and go

around corners, though their energy may be

reduced depending on the angle and the

roughness of the surface. Sometimes sound

waves can be channeled to focus in a certain

direction. As an example, get a long tube, like

the ones for wrapping paper. Use one of the

projects that make a continuous tone, such as

projects 6 or 92. Hold one end of the tube next

to the speaker (use the yellow side with the

grating) and the other end near your ear, then

remove the tube and compare the sound

volume at the same distance from the speaker.

The long tube should make the sound

reaching your ear louder, because sound

waves reflect off the tube walls and stay

concentrated, instead of spreading out across

the room.

-10-

Sound Source Level

Threshold of pain 130dB

Chain saw 110dB

Normal conversation 50dB

Calm breathing 10dB

Hearing threshold 0dB

Surround sound

Sonic boom

It’s hard to perceive

sound direction

underwater.

Placing a long tube next to

the speaker keeps its sound

waves together longer.

Sound waves

Long tube

Speaker

Sound in Our World

Some of a sound wave’s energy can reflect off

walls or objects and come back to you.

Normally you don’t notice these reflections

when you are speaking because not all of the

energy is reflected, and the delay is so short

that your ears can’t distinguish it from the

original sound, but sometimes (such as in a

very large open room) you can hear them -

these are echoes! You hear an echo when a

lot of the energy of your voice is reflected back

to you after a noticeable delay. The delay time

is the distance (to the reflection point and

back) divided by the speed of sound. Most

people cannot distinguish reflected sound

waves with delays of less than 1/15 of a

second, and perceive them as being part of

the original sound. Echoes can be simulated

electronically by replaying a recorded sound

with a small delay and at reduced volume. See

project 10 and others for examples.

In project 10, if your speaker is too close to

your microphone then the echo sound can be

picked up by the microphone and echoed

again and again until you can’t hear anything

else. The same thing can occur in telephone

systems, and these systems sometimes have

echo-cancelling circuitry to prevent problems

(especially in overseas calls, where the

transmission delay times may be longer).

Engineers developing sensitive audio

equipment need to make very accurate sound

measurements. They need rooms that are

sealed from outside sounds, and need to

minimize the measured signal’s reflections off

the walls/ceiling/floor. Specialized rooms have

been designed for this, called anechoic

chambers. These chambers are virtually

soundproof and have specially shaped

materials (usually made of foam) on the walls

to absorb sound waves without producing any

echoes. These chambers simulate a quiet,

open space, allowing the engineers to

accurately measure the equipment being

tested.

Everything has a natural frequency, its

resonance frequency, at which it will vibrate

more easily. When sound waves strike an

object at its natural frequency, the object can

absorb and store significantly more energy

from the sound waves, as vibration. To help

understand this concept, think of a playground

swing, which tends to always swing back and

forth at the same rate. If you push the swing at

the ideal moment, it will absorb energy from

you and swing higher. You don’t need to push

the swing very hard to make it go high, you just

need to keep adding energy at the right

moment. In project 13 (Sound Energy

Demonstration), the frequency is tuned to the

speaker’s natural frequency, making it vibrate

noticeably.

Resonance is an important consideration in

the design of musical instruments, and also in

construction. If high winds blow on a tall

building or a bridge at the structure’s resonant

frequency, vibrations can slowly increase until

the structure is torn apart and collapses.

A cone can help you project your voice. A cone

keeps the sound waves (air pressure

variations) together longer, so they don’t

spread out so quickly. Long ago, people who

had trouble hearing used an ear trumpet,

which helps collect sound waves. A person

would speak into the wide end of the ear

trumpet, and the trumpet makes the sound

louder at the listening person’s ear. Electronic

hearing aids have replaced ear trumpets.

Doctors use a stethoscope to hear inside

patient’s bodies. A stethoscope uses a cone-

like structure to collect sound waves; then

passes them into the doctor’s ear.

-11-

Sound waves reflecting off a wall

Anechoic chamber

Small pushes at the right

moment will make the swing

go higher.

Sound in Our World

Electronically we amplify sound by converting

the sound waves into an electrical signal,

amplify the electrical signal, and then convert

that back to sound waves.

There are many other applications for sound

waves. Here are some examples:

In SONAR (short for SOund Navigation And

Ranging), sound waves are sent out underwater

at various frequencies and the echoes are

measured; the distance to any objects can be

determined using the time for the echoes to

arrive, and the speed of sound. SONAR is used

for navigating around underwater obstacles and

for detecting other ships, especially submarines.

SONAR is also used by the fishing industry to

help find and harvest fish. Sound waves can

also be used to determine the depth of an oil

well. RADAR (RAdio Detection And Ranging) is

similar to SONAR but uses radio waves instead

of sound waves.

Ultrasound waves are above 20 kHz, beyond

the range of human hearing. Bats use

ultrasound waves to effectively “see” in the

dark. Ultrasound waves are also used in

medical imaging, to create pictures of muscles

and organs in the human body. Ultrasound

waves are sometimes used in cleaning items

like jewelry.

Ultrasonic welding is used in industry to bond

materials (usually plastics) together using high

frequency sound waves. The energy of the

sound waves is concentrated at the points to

be bonded, and basically melts the material at

the contact points. This can create a strong

bond, without using glue or nails. Ultrasonic

welding has been used to bond the bottoms of

Snap Circuits®parts in the past, and might still

be used for the speaker (SP2) and

microphone (X1).

Earthquakes are compression waves, similar

to sound waves but with enormous power.

Using triangulation from several measurement

points, and knowing how fast these waves can

travel across the earth’s surface, scientists can

determine where the earthquake began (called

the epicenter).

Music

The subject of music is one where the worlds

of art and science come together.

Unfortunately, the artistic/musician field works

with qualities that depend on our feelings and

so are difficult to express using numbers while

science/engineering works with the opposite -

clearly defined, measurable qualities. As a

result, some of the terms used may seem

confusing at first, but you will get used to them.

Music is when vibrations (creating sound

waves) occur in an orderly and controlled

manner forming a pattern with their energy

concentrated at specific frequencies, usually

pleasant to listen to. Noise is when the

vibrations occur in an irregular manner with

their energy spread across a wide range of

frequencies, usually annoying to hear (static

on a radio is a good example). Notice how

some people refer to music that they don’t like

as noise. In electrical systems, noise is

undesired interference that can obscure the

signal of interest.

Another way to think of this is that the ear tries

to estimate the next sounds it will hear. Music

with a beat, a rhythm, and familiar instruments

can be thought of as very predictable, so we

find it pleasant to listen to. Notice also that we

always prefer familiar songs to music that we

are hearing for the first time. Sudden, loud,

unpredictable sounds (such as gunfire, a glass

breaking, or an alarm clock) are very

-12-

Cone

Ear Trumpet Stethoscope

Horn

Anvil or jig

Plastic

parts

Phase 1 Phase 2 Phase 3

Pressure is applied

by the horn.

The horn vibrates

the plastic parts

very quickly.

The plastic parts

melt together from

the friction created.

SONAR

Ultrasonic welding

Ultrasound photo of a heart (echocardiogram)

Sound in Our World

unnerving and unpleasant. Most electronic

speech processing systems being developed

use some form of speech prediction filters.

Take a piece of string or rope roughly 4 feet

long and tie one end of it to a chair or other

piece of furniture. Swing the other end up and

down so that you have a cyclic pattern, as

shown:

Now swing it three times as fast (three times

the frequency), to produce this pattern:

Now try to swing it five times as fast (five times

the frequency), to produce this pattern:

Since the later patterns are frequency

multiples of the first, we refer to them as

overtones (the music term) or harmonics (the

electronics term) and the original pattern is

called the fundamental. If you could combine

all three of the above patterns onto the string

then you would get a pattern, which looks like

this:

This combined pattern (a single fundamental

with overtones) is called a tone (and a pure

tone is a single fundamental with no

overtones). Notice that each pattern is more

difficult to produce than the one before it, with

the combined pattern being quite complicated.

And also notice that the more complicated

patterns are much more interesting and

pleasing to look at than the simpler ones. Well

the same thing applies to sound waves.

Complex patterns that have many overtones

for each fundamental are more pleasant to

listen to than simple patterns. If many

overtones were combined together, the results

would approximate a square wave shape.

All traditional music instruments use this

principle, with the instrument shapes and

materials perfected through the years to

produce many overtones for each fundamental

chord or key that is played by the user. Grand

pianos sound better than upright pianos since

their larger shape enables them to produce

more overtones, especially at lower

frequencies. Concert halls sound better than

small rooms because they are designed for

best overtone performance and to take

advantage of the fact that sound waves can

reflect off walls to produce different overtone

relationships between both of your ears. The

same thing applies to stereo sound. You may

have heard the term acoustics; this is the

science of designing rooms for best sound

effects.

A commonly used musical scale (which

measures pitch) will now be introduced. This

scale is called the equal temperament scale,

expressed in hertz. You might think of this as

a conversion table between the artistic and

scientific worlds since it expresses pitch in

terms of frequency. Each overtone (overtone

0 being the fundamental) is divided into 12

semitones: C, C# (“C-flat”), D, D#, E, F, F#, G,

G#, A, A#, and B. The semitones increase by

the ratio 12:2, or 1.05946. Musical notes

(tones) are the measure of pitch and are

expressed using both the semitone and the

overtone, such as A3, G#4, D6, A#1, and E2.

(frequency in hertz and rounded off)

-13-

Overtone

C C# D D# E F

0 16.4 17.3 18.4 19.4 20.6 21.8

1 32.7 34.6 36.7 38.9 41.2 45.7

2 65.4 69.3 73.4 77.8 82.4 87.3

3 130 139 147 156 165 175

4 262 278 294 311 330 349

5 523 554 587 622 659 698

6 1047 1109 1174 1245 1319 1397

7 2093 2217 2344 2489 2637 2794

8 4186 4435 4698 4978 5274 5588

9 8372 8870 9397 9956 10548 11175

Overtone

F# G G# A A# B

0 23.1 24.5 26.0 27.5 29.1 30.9

1 46.2 49.0 51.9 55.0 58.3 61.7

2 92.5 98.0 104 110 117 123

3 185 196 208 220 233 247

4 370 392 415 440 466 494

5 740 784 831 880 932 988

6 1480 1568 1661 1760 1865 1976

7 2960 3136 3322 3520 3729 3951

8 5920 6271 6645 7040 7459 7902

9 11840 12542 13290 14080 14917 15804

Sound in Our World

On your U26 keyboard, the blue keys

approximate the 5th overtone notes, and the

green keys approximate the 6th overtone

notes; actual frequency may vary from the

musical scale. The tone of the green keys can

be adjusted with the tune knob, allowing them

to be in tune with the blue keys, or out of tune

with them. The tone of the green keys may

also be adjusted using external resistors and

capacitors, which can change the frequency

range dramatically (and even beyond the

hearing range of your ears), and can create an

optical theremin. Your keyboard can play one

blue note and one green note at the same

time; if you press two keys of the same color

at the same time, only the higher note will be

played. Projects 1-4 and 25-27 demonstrate

the capabilities of the U26 keyboard.

On most instruments, when you play a note

the sound produced is initially loud and then

decreases with time. On your U26 keyboard,

a note ends when you release the key, unless

you connected external resistors to produce a

continuous tone. More complex electronic

instruments can simulate more notes at the

same time, have more advanced techniques

for producing overtones, and continue to play

the note with decreasing loudness after the

key has been released.

The musical world’s equivalent to frequency

is pitch. The higher the frequency, the higher

the pitch of the sound. Frequencies above

2,000 Hz can be considered to provide treble

tone. Frequencies about 300 Hz and below

provide bass tone.

Up to now, the musical measures of pitch and

loudness have been discussed. But many

musical sounds have the same pitch and

loudness and yet sound very different. For

example, the sound of a guitar compared to

that of a piano for the same musical note. The

difference is a quality known as timbre. Timbre

describes how a sound is perceived, its

roughness. Scientifically it is due to differences

in the levels of the various overtones, and so

cannot be expressed using a single number.

Now consider the following two tones, which

differ slightly in frequency:

If they are played at the same time then their

sound waves would be added together to

produce:

Notice that the combined wave has a regular

pattern of where the two tones add together

and where they cancel each other out. This is

the effect that produces the beat you hear in

music. Two tones (that are close in frequency

and have similar amplitude for their

fundamental and for each of their overtones)

will beat at the rate of their frequency

difference. Rhythm is the pattern of regular

beat that a song has.

Now observe this tone:

The frequency is slowly increasing and

decreasing in a regular pattern. This is an

example of vibrato. If the frequency is

changing slowly then it will sound like a varying

pitch; a fast vibrato (several times a second)

produces an interesting sound effect. The

alarm IC (U2, included in Snap Circuits®

models SC-100, 300, 500, or 750) produces

sounds using the vibrato effect.

Tempo is a musical term, which simply

describes how quickly a song is played.

-14-

DO’s and DON’Ts of Building Circuits

After building the circuits given in this booklet, you may wish to experiment on your own.

Use the projects in this booklet as a guide, as many important design concepts are

introduced throughout them. Every circuit will include a power source (the batteries), a

resistance (which might be a resistor, capacitor, speaker, integrated circuit, etc.), and wiring

paths between them and back. You must be careful not to create “short circuits” (very low-

resistance paths across the batteries, see examples at right) as this will damage

components and/or quickly drain your batteries. Only connect the keyboard (U26), voice

changer (U27), and echo IC (U28) using configurations given in the projects, incorrectly

doing so may damage them. ELENCO®is not responsible for parts damaged due to

incorrect wiring.

Here are some important guidelines:

ALWAYS USE EYE PROTECTION WHEN EXPERIMENTING ON YOUR OWN.

ALWAYS include at least one component that will limit the current through a circuit, such

as the speaker, capacitors, ICs (which must be connected properly),

microphone, or resistors.

ALWAYS use LEDs, transistors, and switches in conjunction with other components that

will limit the current through them. Failure to do so will create a short circuit

and/or damage those parts.

ALWAYS connect capacitors so that the “+” side gets the higher voltage.

ALWAYS disconnect your batteries immediately and check your wiring if something

appears to be getting hot.

ALWAYS check your wiring before turning on a circuit.

ALWAYS connect the keyboard (U26), voice changer (U27), and echo IC (U28) using

configurations given in the projects or as per the connection description on

pages 6 and 7.

NEVER connect to an electrical outlet in your home in any way.

NEVER leave a circuit unattended when it is turned on.

NEVER use headphones at high sound levels.

For all of the projects given in this book, the parts may be arranged in different ways without

changing the circuit. For example, the order of parts connected in series or in parallel does

not matter — what matters is how combinations of these sub-circuits are arranged together.

Placing a 3-snap wire directly

across the batteries is a

SHORT CIRCUIT.

This is also a

SHORT CIRCUIT.

When the slide switch (S1) is turned on, this large circuit has a SHORT

CIRCUIT path (as shown by the arrows). The short circuit prevents any

other portions of the circuit from ever working.

NEVER

DO!

NEVER

DO!

NEVER

DO!

Examples of SHORT CIRCUITS - NEVER DO THESE!!!

Warning to Snap Circuits®owners: Do not connect

additional voltage sources from other sets, or you

may damage your parts. Contact Elenco®if you have

questions or need guidance.

You are encouraged to tell us about new programs and circuits you

create. If they are unique, we will post them with your name and state

on our website at:

www.snapcircuits.net/learning_center/kids_creation

Send your suggestions to ELENCO®: elenco@elenco.com.

ELENCO®provides a circuit designer so that you can make your own

Snap Circuits®drawings. This Microsoft®Word document can be

downloaded from:

www.snapcircuits.net/learning_center/kids_creation

or through the www.snapcircuits.net website.

WARNING: SHOCK HAZARD - Never connect Snap Circuits®

to the electrical outlets in your home in any way!

NEVER

DO!

-15-

Advanced Troubleshooting

(Adult supervision recommended)

ELENCO®is not responsible for parts

damaged due to incorrect wiring.

If you suspect you have damaged parts,

you can follow this procedure to

systematically determine which ones

need replacing:

(Note: Some of these tests connect an LED

directly across the batteries without another

component to limit the current. Normally this

might damage the LED, however Snap Circuits®

LEDs have internal resistors added to protect

them from incorrect wiring, and will not be

damaged.)

1. Color LED (D8), speaker (SP2), and

battery holder (B1): Place batteries in

holder. Place the color LED directly across

the battery holder (LED + to battery +), it

should light and be changing colors. “Tap”

the speaker across the battery holder

contacts; you should hear static as it

touches. If neither works, then replace

your batteries and repeat. If still bad, then

the battery holder is damaged. Test both

battery holders.

2. Red & black jumper wires: Use this

mini-circuit to test each jumper wire; the

LED should light.

3. Snap wires: Use this mini-circuit to test

each of the snap wires, one at a time. The

LED should light.

4. Slide switch (S1) and Press switch (S2):

Use this mini-circuit; if the LED doesn’t

light then the slide switch is bad. Replace

the slide switch with the press switch to

test it.

5. 100W (R1) and 5.1kW (R3) resistors, and

microphone (X1): Use this mini-circuit;

the LED will be bright if the R1 resistor is

good. Next use the 5.1kWresistor in place

of the 100Wresistor; the LED should be

much dimmer but still light. Next, replace

5.1kWresistor with the microphone (“+” to

right); the LED should flicker dimly but still

light.

6. 500kWadjustable resistor (RV3) and

Photoresistor (RP): Use the mini-circuit

from test 5 but replace the 100Wresistor

with RV3. Turning RV3’s knob all the way

to the left (counter-clockwise) should make

the color LED bright and most other

settings should make the LED dim or off;

otherwise RV3 is bad. Next, replace RV3

with the photoresistor, and shine a bright

light on it. Waving your hand over the

phototransistor (changing the light that

shines on it) should change the brightness

of the color LED; otherwise the

photoresistor is bad.

7. Adjustable resistor (RV): Build project

98. Move the resistor control lever to both

sides. The color LED (D8) should be bright

if the lever is to the far left or far right, and

dim if the lever is in the middle.

8. NPN transistor (Q2): Build the mini-

circuit shown here. The color LED (D8)

should only be on if the press switch (S2)

is pressed. If otherwise, then Q2 is

damaged.

-16-

Advanced Troubleshooting

(Adult supervision recommended)

9. Keyboard (U26): Build project 92, but

omit the 0.1mF capacitor (C2) and the

5.1kWresistor (R3). You should hear a

tone when you press any key. Turning the

TUNE knob while pressing any green key

should change the tone slightly. Now add

R3 to the circuit, and you should hear a

continuous tone. If any of this does not

work then the keyboard is damaged.

10. 0.1mF (C2), 1mF (C7), and 470mF (C5)

capacitors: Build project 92; removing

C2 from it should change the tone, or C2

is damaged. Next, replace C2 with C7; the

pitch of the tone should be lower now, or

C7 is damaged. Next, replace C7 with C5;

you should hear a click every few seconds,

or C5 is damaged.

11. Voice changer (U27): Build project 7.

Follow the project’s instructions to confirm

that you can make a recording and play it

back at different speeds.

12. Echo IC (U28): Build the circuit shown at

right, turn it on, and set the knob on the

500kWadjustable resistor (RV3) to the

right. Press any keys on the keyboard; you

should hear tones with echo, and be able

to adjust echo level using the lever on the

adjustable resistor (RV). Removing the

1mF capacitor (C7) should reduce the

volume a little. Sometimes an echo IC

problem can be fixed by turning the circuit

off and back on to reset it.

12. Audio Jack (JA) and stereo cable: If

you have headphones, use them to test

the audio jack using project 14. If you have

a music device, use it to test the audio jack

using project 66. Use project 66 to test

your stereo cable.

13. Sound energy demonstration container:

If the flexible sheet is damaged,

disassemble the container and replace the

flexible sheet; this set may have included

a spare for it, or you can use household

plastic wrap.

ELENCO®

150 Carpenter Avenue

Wheeling, IL 60090 U.S.A.

Phone: (847) 541-3800

Fax: (847) 520-0085

e-mail: help@elenco.com

Website: www.elenco.com

You may order additional / replacement

parts at: www.snapcircuits.net

-17-

Project # Description Page #

1 Electronic Keyboard 20

2 Aligning the Keyboard 20

3 Be a Musician 21

4 Be a Musician (II) 21

5 Optical Theremin 22

6 Keyboard Slider 22

7 Voice Changer 23

8 Voice Changer & Light 23

9 Color Light 23

10 Echo 24

11 Echo with Headphones 24

12 Louder Echo with Headphones 24

Sound Energy Demonstration

25,26

14 Keyboard in Stereo 27

15 Optical Theremin in Stereo 27

16 Light & Sound 28

17 See Saw 28

18 Light, Sound, & Motion 29

19 Brighter Light, Sound, & Motion 29

20 Keyboard with Voice Changer 30

Optical Keyboard with Voice Changer

Keyboard Voice Changer & Light

23 Voice Changer with Echo 31

24 Sound Controlled Light 31

25 Low Pitch Keyboard 32

26 Lower Pitch Keyboard 32

27 Very Low Pitch Keyboard 32

28 Echo Speed Changer 32

29 Keyboard Echo 33

30 Lower Pitch Keyboard Echo 33

31 Optical Keyboard Echo 33

Project # Description Page #

Low Pitch Optical Keyboard Echo

Keyboard Echo with Stereo Effects

34 Optical Echo in Stereo 35

35 Color Short Light 35

36 Keyboard with Optical Theremin 36

Keyboard with Optical Theremin (II)

Adjustable Dual Range Keyboard

Adjustable Dual Range Keyboard (II)

Adjustable Dual Range Keyboard (III)

41 Your Music with Echo 37

42 Your Music with Echo and Light 37

43 Your Music Speed Changer 38

44 Your Music Speed Changer (II) 38

45 Your Music Speed Changer (III) 38

46 Sound On Light 38

47 Super Optical Keyboard Echo 39

48 Softer Optical Keyboard Echo 39

49 Reflection Detector 39

Super Optical Keyboard Echo for Headphones

51 Sound is Air Pressure 41

Sound is Air Pressure - Keyboard

53 Brightness Adjuster 42

54 Brightness Limiters 42

55 Big Brightness Adjuster 42

56 Photo Brightness Adjuster 43

Amplified Photo Brightness Adjuster

Amplified Big Brightness Adjuster

59 Cup & String Communication 44

60 Audio Amplifier 45

61 Low Power Audio Amplifier 45

62 Audio Amplifier with L/R Control 45

Project # Description Page #

63 Your Music without Echo 46

Low Power Your Music without Echo

65 Adjustable Music without Echo 46

66 L/R Music Amplifier 47

67 Another Transistor Amplifier 47

68 Microphone Resistance - LED 48

69 Microphone Resistance - Audio 48

70 Time Light 49

71 Time Light (II) 49

72 Easier Adjust Time Light 49

73 Small Adjust Time Light 49

74 Day Light 50

75 Lower Day Light 50

76 Dark Light 50

77 Blow Noise 50

78 Listen to the Light Change 51

Adjustable Listen to the Light Change

80 Bright or Loud? 51

81 LED Keyboard Control 52

82 LED Keyboard Control (II) 52

83 Photo LED Keyboard Control 52

Adjustable LED Keyboard Control

85 Capacitor Keyboard Control 53

86 Capacitor Keyboard Control (II) 53

87 Voice & Keyboard Echo 53

88 LED Voice & Keyboard Echo 54

89 Photo LED Keyboard Echo 54

90 Photo LED Keyboard 54

91 Audio Dark Light 54

92 Oscillator 55

93 Oscillator (II) 55

Project Listings

-18-

Project # Description Page #

94 Oscillator (III) 55

95 Oscillator (IV) 55

96 Oscillator (V) 55

97 Oscillator (VI) 55

98 Left Right Bright Light 55

99 Adjustable Oscillator 56

100 Adjustable Oscillator (II) 56

101 Adjustable Oscillator (III) 56

102 Adjustable Oscillator (IV) 56

103 Water Detector 56

104 Clicker 57

105 Clicker with Echo 57

106 3V Audio Amplifier 58

107 Mini Music Player 58

108 Voice Echo with Light 58

109 Color Sound 59

110 Color Sound (II) 59

111 Color Sound (III) 59

112 Backwards Color Sound 59

113 White Light 60

114 Red to White 60

115 Alarm 60

116 Super Voice Echo with Light 61

117 Press Echo 61

118 Photo Echo 61

119 Loud Press Photo Echo 61

120 Knob Echo 61

121 Echo Light Headphone 62

122

Echo Light Headphone Variants

123 Press Echo Light 62

124 Photo Echo Light 62

125 Another Voice Echo Light 63

Project # Description Page #

126 Daylight Voice Echo 63

127 Dark Voice Echo 64

128 Dark Echo Light 64

129 Dark Echo Variants 64

130 Day Echo Light 65

131 Day Echo Variants 65

132 Photo Light Timer 65

133 Adjustable Photo Light Timer 65

134 Tone Stoppers 66

135 Tone Stoppers (II) 66

136 Tone Stoppers (III) 66

137 Tone Stoppers (IV) 66

138 Tone Stoppers (V) 67

139 Alarm Light 67

140

Voice Changer with Headphones

141 Day Keyboard 68

142 Night Keyboard 68

143 Color Keyboard 69

144 Color Keyboard (II) 69

145 Color Keyboard (III) 69

146 Color Keyboard (IV) 69

147 Color Keyboard (V) 70

148 Color Keyboard (VI) 70

149

Adjustable Voice Changer & Light

150

Adjustable Voice Changer & Light (II)

151 Play Fast 71

152 Red First 71

153 Adjustable Timer Tone 72

154 Photo Timer Tone 72

155 Delay Lamp 72

156 Adjustable Delay Lamp 72

157 Water Alarm 73

Project # Description Page #

158 Continuity Tester 73

159 High Low Light 73

160 Flicker Clicker 74

161 Fast Flicker Clicker 74

162 Slow Flicker Clicker 74

163 Timer Tone 74

164 Little Battery 75

165 Tiny Battery 75

166 Little Battery Beep 75

167 Capacitors in Series 76

168 Capacitors in Series (II) 76

169 Capacitors in Series (III) 76

170 More Capacitors in Series 76

171 Capacitors in Parallel 77

172 Capacitors in Parallel (II) 77

173 Capacitors in Parallel (III) 77

174 More Capacitors in Parallel 77

175 Resistors in Series 78

176 Resistors in Parallel 78

177 Lots of Resistors in Series 79

178 Lots of Resistors in Parallel 79

179 Be a Loud Musician 80

180 Be a Loud Musician (II) 80

181 Morse Code 81

182 Transistor Audio Amplifier 82

183 Transistor Audio Amplifier (II) 82

184 Make Your Own Parts 83

185 Color Touch Light 83

186 Test Your Hearing 84

187 See the Sound 84

188 See the Spectrum 85

Project Listings

-19-

Project 1 Electronic Keyboard

Placement Level

Numbers

Snappy says the green keys

have approximately double

the pitch (frequency) of the

blue keys. When the blue

and green keys have been

aligned using the TUNE

knob, then they have

(almost) exactly double the

pitch, and sound good

together because they are in

harmony.

Placement Level

Numbers

(1-snap wire is placed

under the speaker)

Project 2 Aligning the Keyboard

Use the preceding circuit. Press one of the green

keys and turn the TUNE knob on the keyboard to

adjust the pitch of the tone. The TUNE knob will

not affect the blue keys.

Now turn the TUNE knob while pressing the blue

C key and the green C key at the same time.

Slowly turn the knob across its entire range, and

see how the sound varies. At most TUNE knob

positions you will notice separate tones from the

blue and green keys, but there will be a knob

position where the blue and green tones blend

together and seem like a single musical note - this

is the best TUNE setting to play songs with. The

blue and green keys are now aligned together.

Snap Circuits®uses electronic blocks that snap onto

a clear plastic grid to build different circuits. These

blocks have different colors and numbers on them

so that you can easily identify them.

Build the circuit shown on the left by placing all the

parts with a black 1next to them on the board first.

Then, assemble parts marked with a 2. Then,

assemble the part marked with a 3. Note that the 1-

snap wire is placed beneath the speaker (SP).

Install two (2) “AA” batteries (not included) into each

of the battery holders (B1) if you have not done so

already.

Turn on the slide switch (S1), and press any of the

keys on the keyboard (U26) to hear tones. Two

tones may be played at the same time, one tone

from the blue keys and one tone from the green

keys. If you press two keys of the same color then

the higher pitch one will be played.

-20-

To play a song, just press the key corresponding with the letter shown. If

there is a “–” after a letter, press the key longer than usual.

Mary Had a Little Lamb

E D C D E E E– D D D– E G G–

Ma-ry had a lit-tle lamb, Lit-tle lamb, lit- tle lamb.

E D C D E E E E D D E D C–––

Ma-ry had a lit-tle lamb, Whose fleece was white as snow.

Row, Row, Row Your Boat

C– C– C D E– E D E F G–––

Row, row, row your boat, Gen-tly down the stream.

C C C G G G E E E C C C G F E D C–––

Mer-ri-ly, mer-ri-ly, mer-ri-ly, mer-ri-ly, Life is but a dream.

The Farmer in the Dell

––G C C C C C–– D E E E E

The far-mer in the dell, The far-mer in the

E–– G– G A G E C D E E D D C––

dell, Heigh-ho the der-ry-oh, the far-mer in the dell.

Muffin Man

D G G A B C G F# E A A G F# D D

Do you know the muf-fin man, The muf-fin man, the muf- fin man?

D G G A B G G G A A D D G––

Do you know the muf-fin man Who lives on Dru-ry Lane?

Twinkle, Twinkle, Little Star

C C G G A A G F F E E D D C–

Twin-kle, twin-kle, lit-tle star, How I won-der what you are.

G G F F E E D– G G F F E E D–

Up a-bove the world so high, Like a dia-mond in the sky.

C C G G A A G F F E E D D C––

Twin-kle, twin-kle, lit-tle star, How I won-der what you are.

Rain, Rain, Go Away

G E G G E G G E A G G E

Rain, rain, go a-way. Come a-gain some o-ther day.

F F D D D F F D G F E D E C C–

We want to go out- side and play. Rain, rain, go a-way.

For He’s a Jolly Good Fellow

––C E E E D E F E E D D D C D

For he’s a jol-ly good fel-low, For he’s a jol-ly good

E C D E E E D E F– A A G G G F D C–

–

fel-low, For he’s a jol-ly good fel-low, Which no-bo-dy can de- ny.

Ring Around the Rosy

G G E A G E F G G E A G E

Ring a-round the ro-sy, A poc-ket full of pos-ies,

F D F D F G G C–

Ash-es, ash-es, We all fall down!

Mystery song (see if you recognize it)

C C D C F E–

C C D C G F–

C C CA F F E

A# A# A F G F–

Project 3 Be a Musician

Project 4 Be a Musician (II)

Use the preceding circuit and songs, but press both the blue and green keys

for each note, at the same time. Try this with the blue and green keys aligned

(as per project 2), but also try them at different TUNE knob settings (so the

keys are out of alignment.

-21-

Some songs have

been modified to make

them easier to play on

your keyboard.

Project 5

Optical Theremin

A theremin is an electronic musical instrument where

you change the sound by moving your hands around

near it (without touching it); using the tiny changes

your hands have on the electromagnetic field of an

antenna. This circuit is an optical theremin because

instead you adjust the sound by changing the amount

of light reaching a photosensor (the photoresistor).

Project 6

Keyboard Slider

Modify the preceding circuit to match this one. Turn on both slide

switches (S1), and move the lever on the adjustable resistor (RV)

around to change the sound. At some settings there may not be any

sound.

You can play the keyboard (U26) keys while changing the sound with

the adjustable resistor, to get a combination of sound effects. Turn off

the left slide switch to disable the adjustable resistor sound effects.

Build the circuit as shown. Turn on both slide switches (S1), and move

your hand over the photoresistor (RP). You can adjust the sound just

by moving your hand around. See what range of sounds you can

produce, then change the amount of light in the room, and see how

sound the range of sounds has changed. There may not be any sound

if there is too much or too little light on the photoresistor.

You can play the keyboard (U26) keys while adjusting the sound using

the photoresistor, to get a combination of sound effects. Turn off the left

slide switch to disable the photoresistor sound effects.

-22-

Project 7 Voice Changer

Placement Level

Numbers

Project 9 Color Light

LEDs (Light Emitting Diodes)

convert electrical energy into light;

the color of the light emitted

depends on the characteristics of

the material used in them.

The color LED actually contains

separate red, green, and blue

lights, with a micro-circuit

controlling them.

Project 8

Voice Changer & Light

Build the circuit as shown. Turn on the slide switch

(S1), and enjoy the light show from the color LED

(D8). For best effects, place the egg LED attachment

on the color LED, and dim the room lights.

Use the preceding circuit, but replace the

3-snap wire that is next to the speaker

(SP2) with the color LED (D8, “+” to the

left). Now when you press S2 to play the

recording, the sound will not be as sound,

but the color LED will be flashing.

Build the circuit shown on the left by placing all the parts with a black

1next to them on the board first. Then, assemble parts marked with

a 2. Then, assemble the part marked with a 3. Install two (2) “AA”

batteries (not included) into each of the battery holders (B1) if you

have not done so already. Be sure to install the microphone (X1)

with its “+” side positioned as shown.

Set the 500kWadjustable resistor (RV3) to mid-range, turn OFF the

left slide switch (S1), and then turn on the right slide switch. Now

turn on the left slide switch, you hear a beep signaling that you may

begin recording. Talk into the microphone until you hear a beep

(signaling that recording time is over), then turn off the left slide

switch to exit recording mode. Push the press switch (S2) to play

back the recording, and turn the knob on RV3 to change the

playback speed. You can play your recording faster or slower by

changing the setting on RV3.

Recording time is 6 seconds at normal speed, but this can be

changed depending on the setting of RV3 when you are making the

recording.

Egg LED

Attachment

-23-

Build the circuit as shown, and connect your own

headphones (not included in this set) to the audio

jack (JA). Turn on the bottom slide switch (S1).

Talk into the microphone, and listen the echo on your

headphones. Set the 500kWadjustable resistor (RV3)

for most comfortable sound level (turn to the left for

higher volume, most of RV3’s range will be very low

volume), then adjust the amount of echo using the

lever on the adjustable resistor (RV); move the lever

up for more echo or down for less echo. Try this at

different RV settings, because the effects are very

interesting with both high and low echo amounts. Also

try it while saying different words/sounds.

Turn on the top slide switch to make the sound

louder, or turn it off to make the sound softer.

Project 10

Echo

Project 11

Echo with Headphones

Project 12

Louder Echo

with

Headphones

(not included)

WARNING: Headphones performance

varies, so use caution. Start with low volume,

and then carefully increase to a comfortable

level. Permanent hearing loss may result from

long-term exposure to sound at high volumes.

Turning on the top slide switch

adds the 0.1mF capacitor (C2)

to the circuit, which increases

the amplification in the echo

IC. With headphones, the

sound can be made louder

because the microhone does

not pick it up easily.

Build the circuit as shown, and place it in a quiet

room. Connect the speaker (SP2) using the red &

black jumper wires, and then hold it away from the

microphone (X1). Turn on the slide switch (S1). Talk

into the microphone, and listen the echo on the

speaker. Adjust the amount of echo using the lever

on the adjustable resistor (RV); move the lever up

for more echo or down for less echo. Try this at

different RV settings, because the effects are very

interesting with both high and low echo amounts.

Also try it while saying different words/sounds.

Note: you must hold the speaker away from the

microphone or the circuit may self-oscillate due to

feedback. You also need a quiet room, with low

background noise.

Use the preceding circuit,

but replace the 0.1mF

capacitor (C2) with the 1mF

capacitor (C7). The sound is

louder now when both slide

switches (S1) are on.

If you hold your headphones

next to the microphone (X1),

you may hear a whining

sound, because the

headphones sound might be

picked up by the

microphone and be echoed

again and again and again.

If the speaker is too close to the

microphone, then the speaker’s sound

will be picked up by the microphone and

be echoed again and again and again,

until you can’t hear anything else. The

same thing can happen if the room is too

noisy, or if you talk too loud.

-24-

Project 13 Sound Energy Demonstration

Pour salt, glitter, or small foam/candy

balls (not included) into the container,

but do not cover the bottom.

Assemble the Sound energy demonstration container (as per page 4, or

shown on next page) if you have not done so already. Build the circuit as

shown. Turn off the left slide switch (S1) and turn on the right slide switch.

Lay the speaker (SP2) down on the unused 3-snap and 6-snap wires (to

elevate it slightly off the table); be sure it is lying flat, and place the sound

energy demonstration container over it. Pour some salt, glitter, small foam

or candy balls of 0.1 inch diameter or less (not included) or similar into the

container, but not enough to cover the bottom.

Press the keys on the keyboard to make sound. For some keys the

salt/glitter/balls will vibrate and bounce or dance around in the container,

find the key that gives the best effects. Most keys will create little or no

vibration. For the best key, adjust the TUNE knob on the keyboard for best

effects.

Now turn on the left slide switch and move the lever on the adjustable

resistor (RV) around. At some positions the salt/glitter/balls will vibrate and

bounce or dance around in the container; find the setting that gives the

best effects. Press some keyboard keys to add more sound effects.

Experiment with different materials in the container and see which give

the most impressive results. Our engineers found that nonpareils (round

decorative candy sprinkles) of up to 0.1” work best.

Try lifting the container a little higher above the speaker with your hands,

and see how much this affects the bounce height; see where you get the

best effects. Try it at best key or RV setting, and at other keys/settings.

Also, placing the speaker directly on the table (without the 3-snap and 6-

snap under it) should reduce the vibration a little, but you can try it to see

the difference.

Try removing the 0.1mF capacitor (C2), and see how the sounds and

bounce effects change. Next, remove the sound energy demonstration

container from the speaker and instead lay your hand on it for the best

setting, you can feel the speaker vibrate.

Don’t eat anything you placed into the sound energy demonstration

container.

The bouncing salt/

glitter/balls show

that sound has

energy!

Typically the

E keys and the keys

near them give the

best effects, but your

results may vary.

Lay the speaker on the extra 3-snap

and 6-snap wires, to elevate it. Be

sure speaker lays flat.

-25-

Tube

Flexible sheet

Container base

Speaker

Sound Energy Demonstration

Container Assembly

(Adult supervision recommended)

Pour salt, glitter, or small

foam/candy balls into the

container, but do not cover

the bottom.

Lay the speaker on the extra 3-snap and 6-snap

wires, to elevate it. Be sure speaker lays flat.

Part B: Optical Version

Modify the circuit to be this one, which has the

photoresistor (RP) instead of the adjustable

resistor (RV).

Turn on both slide switches and wave your hand

over the photoresistor (RP), to change how much

light shines into it. The sound changes as your

hand adjusts the light. At some hand positions the

salt/glitter/balls will vibrate and bounce or dance

around in the container; find the hand position that

gives the best effects. Press some keyboard keys

to combine their sounds with the photoresistor

sound. Try moving to an area with more or less

light, and wave your hand over the photoresistor

again.

Don’t eat anything you placed into the sound

energy demonstration container.

How does this work? There is a small range of

frequency at which the sound waves resonate

with the mechanical construction

characteristics of the speaker, and cause the

speaker to vibrate noticeably. The speaker’s

vibration creates changes in air pressure. The

sound energy demonstration container covers

the speaker and traps the air pressure

changes, which then push/pull the flexible

sheet up/down quickly, making the

salt/glitter/balls bounce. Raising the speaker

and container by placing them on the snap

wires (or holding them) makes the vibrations

more noticeable, because otherwise the table

can dampen the vibrations.

-26-

This project requires stereo headphones or a stereo speaker; neither is included

with this set, but this set does include a stereo cable to facilitate connection to

your stereo speaker.

Build the circuit as shown. Connect your own headphones or stereo speaker to

the audio jack (JA). Turn on the slide switch (S1).

Press keys on the keyboard (U26) and listen to the sound on your headphones

or stereo speaker. Set the 500kWadjustable resistor (RV3) for most comfortable

sound level (turn to the left for higher volume, most of RV3’s range will be very

low volume), and then move the lever on the adjustable resistor (RV) to vary

the amplitude to each ear.

Project 14

Keyboard in Stereo

Project 15

Optical Theremin in Stereo

Headphones or

Stereo Speaker

(not included)

In stereo, sound is produced on several

speakers with varying amplitude on each.

This gives the impression that the sound

is coming from different directions.

WARNING: Headphones performance varies, so use caution. Start with

low volume, then carefully increase to a comfortable level. Permanent

hearing loss may result from long-term exposure to sound at high volumes.

Use the preceding circuit, but modify it by adding the photoresistor (RP) and

the parts next to it.

Press keys on the keyboard (U26) and wave your hand over the

photoresistor (to adjust the amount of light shining on it) while listening to

the sound on your headphones or stereo speaker. Set the 500kWadjustable

resistor (RV3) for most comfortable sound level (turn to the left for higher

volume, most of RV3’s range will be very low volume), and move the lever

on the adjustable resistor (RV) to vary the amplitude to each ear. There may

not be any sound if there is too much or too little light on the photoresistor.

Close your eyes and have a friend vary the light to the photoresistor and

moving the lever on the adjustable resistor. See if you get an impression of

the sound changing direction.

WARNING: Headphones

performance varies, so use

caution. Start with low volume,

then carefully increase to a

comfortable level. Permanent

hearing loss may result from

long-term exposure to sound

at high volumes.

Headphones or

Stereo Speaker

(not included)

-27-

Project 16

Light & Sound

Project 17

See Saw

Build the circuit as shown; note that a 2-snap wire is placed directly

under the speaker (SP2). Turn off the left slide switch (S1) and turn on

the right slide switch. Press keys on the keyboard (U26) to make sound

on the speaker (SP2) and light on the color LED (D8). If you hold a key

down then the color LED will change colors.

Now turn on the left slide switch. If there is light on the photoresistor

(RP), or if you press keys on the keyboard, then there will be sound

from the speaker and light from the color LED. Wave your hand over

the photoresistor to change the sound, or turn off left S1 to disable

photoresistor control. Holding a key down will also make the color LED

change colors.

-28-

Turn on the slide switch (S1), and move the lever on the adjustable

resistor (RV) around. The pitch of the sound will be lowest with the lever

in the middle position, and higher with it set to the left or right.

You can replace the 5.1kWresistor (R3) with the 100Wresistor (R1) or

500kWadjustable resistor (RV3), but there may be no sound at some

settings.

Project 18

Light, Sound, & Motion

Use the preceding circuit, but replace the 470mF capacitor

(C5) with the 1mF capacitor (C7). The color LED (D8) is

brighter now, but may not be changing colors.

Let’s add motion to the preceding circuit. Modify the circuit to match this

one. Turn off the left slide switch (S1) and turn on the right slide switch.

Lay the speaker (SP2) down on unused 2-snap and 6-snap wires (to

elevate it slightly off the table), be sure it is laying flat, and place the sound

energy demonstration container over it (the container should have been

assembled as per instructions on page 4). Pour some salt, glitter, small

foam or candy balls of 0.1 inch diameter or less (not included) or similar

into the container, but not enough to cover the bottom.

Press the keys on the keyboard to make sound and light the color LED

(D8). For some keys the salt/glitter/balls will vibrate and bounce or dance

around in the container, find the key that gives the best effects. Most keys

will create little or no vibration. For the best key, adjust the TUNE knob on

the keyboard for best effects. The color LED will not be very bright.

Now turn on the left slide switch and wave your hand over the photoresistor

(RP), to change how much light shines into it. The sound changes as your

hand adjusts the light, and the color LED will light if there is bright light on

the photoresistor. At some hand positions the salt/glitter/balls will vibrate

and bounce or dance around in the container; find the hand position that

gives the best effects. Press some keyboard keys to combine their sounds

with the photoresistor sound. Try moving to an area with more or less light,

and wave your hand over the photoresistor again.

Experiment with different materials in the container and see which give

the most impressive results. Our engineers found that 0.1” round non

pareils (decorative candy sprinkles) work best.

Try lifting the container a little higher above the speaker with your hands,

and see how much this affects the bounce height; see where you get the

best effects. Try it at best key or RV setting, and at other keys/settings.

Also, placing the speaker directly on the table (without the 3-snap and 6-

snap under it) should reduce the vibration a little, but you can try it to see

the difference.

Add the 0.1mF capacitor (C2) over the keyboard (U26) at base grid

locations D4-F4 (on level 3) and see how the circuit changed, especially

when pressing the green keys.

Project 19

Brighter Light, Sound, & Motion

Lay the speaker on the

extra 3-snap and 6-snap

wires, to elevate it. Be

sure speaker lays flat.

Place the sound energy

demonstration container over

the speaker. Pour salt, glitter,

or small foam/candy balls (not

included) into the container,

but do not cover the bottom.

-29-

Project 20

Keyboard with Voice Changer

Project 21

Optical Keyboard

with Voice Changer

Project 22

This circuit is similar to the preceding one, but adds optical

control. Modify the preceding circuit by adding the

photoresistor (RP) and the parts next to it.

When making your recording, wave your hand over the

photoresistor to change the sound recorded, in addition to

pressing keys. The photoresistor may have no effect if there is

too much or too little light on it, so adjust the light on it if

necessary.

Use either of the preceding circuits,

but replace the 3-snap wire that is next

to the speaker (SP2) with the color

LED (D8, “+” to the left). Now when

you press S2 to play the recording, the

sound will not be as sound, but the

color LED will be flashing.

Set the 500kWadjustable resistor (RV3) to mid-range, turn OFF

the left slide switch (S1), and then turn on the right slide switch.

Now turn on the left slide switch, you hear a beep signaling that

you are recording. Press keys on the keyboard (U26) until you

hear a beep (signaling that recording time is over), then turn off

the left slide switch to exit recording mode. Push the press

switch (S2) to play back the recording, and turn the knob on

RV3 to change the playback speed. You can play your

recording faster or slower by changing the setting on RV3.

The keyboard overhangs the base grid, so be sure the

connections to it stay secure as you are pressing keys.

Recording time is 6 seconds at normal speed, but this can be

changed depending on the setting of RV3 when you are making

the recording. You won’t hear the notes when you are pressing

the keys during recording; you only hear them during playback.

Keyboard Voice

Changer & Light

-30-

Project 24 Sound Controlled Light

If the adjustable resistor’s lever is set too

low then the color LED will never turn

on; if it is set too high then the color LED

will never turn off.

Project 23

Voice Changer with Echo

Build the circuit as shown. Turn on the switch (S1) and set the lever on

the adjustable resistor (RV) so the color LED (D8) is just off. Talk loud into

the microphone (X1) or clap loudly near it to activate the color LED. Try a

long loud “ahhhhhhhh” directly into the microphone; this can make the

color LED change patterns.

The color LED may not be very bright, so this circuit works best in a dimly

lit room.

Build the circuit as shown; note that the microphone (X1) is covering a

2-snap wire, and that the 5.1kWresistor (R3) is a tight fit over the

adjustable resistor (RV) but does fit. Set the 500kWadjustable resistor

(RV3) to mid-range, set the adjustable resistor (RV) lever towards R3,

turn OFF the left slide switch (S1), and then turn on the right slide

switch.

Now turn on the left slide switch, you hear a beep signaling that you

are recording. Talk into the microphone (X1) until you hear a beep

(signaling that recording time is over), then turn off the left slide switch

to exit recording mode. Now move the lever on RV to set the echo level,

turn the knob on RV3 to change the playback speed, and push the

press switch (S2) to play back the recording. You can play your

recording faster or slower by changing the setting on RV3, and with

more or less echo by changing the setting on RV.

Recording time is 6 seconds at normal speed, but this can be changed

depending on the setting of RV3 when you are making the recording.

RV should be set for no echo when making a recording.

-31-

Project 25

Low Pitch Keyboard

Project 26

Lower Pitch Keyboard

Project 28

Echo Speed Changer

Set the 500kWadjustable resistor (RV3) to mid-range, turn OFF the left

slide switch (S1), and then turn on the right slide switch. Set the echo

level using adjustable resistor (RV). Now turn on the left slide switch, you

hear a beep signaling that you are recording. Talk into the microphone

(X1) until you hear a beep (signaling that recording time is over), then

turn off the left slide switch to exit recording mode. Push the press switch

(S2) to play back the recording, and turn the knob on RV3 to change the

playback speed. You can play your recording faster or slower by

changing the setting on RV3, and with more or less echo by changing

the setting on RV.

Recording time is 6 seconds at normal speed, but this can be changed

depending on the setting of RV3 when you are making the recording.

C2 is only used to support RV, so is only connected on one side.

Use the preceding circuit, but replace

the 1mF capacitor (C7) with the 470mF

capacitor (C5, “+” on left). Press one of

the green keys and hold it down; all you

should hear is a click every few seconds.

Use the preceding circuit, but replace the

0.1mF capacitor (C2) with the 1mF

capacitor (C7). The pitch of the green keys

is much lower now. See how the blue and

green keys sound when pressed together.

Build the circuit as shown. Turn

off the left slide switch and turn on

the right slide switch (S1), and

press some of the green keys.

Now turn on the left slide switch

to add the 0.1mF capacitor (C2) to

the circuit, and press some green

keys again. The pitch (frequency)

of the sound is lower now. The

blue keys will not be affected.

Compare the sound for blue and

green keys at the same place on

the keyboard (such as Cto C, F#

to F#, or Bto B). Turn the TUNE

knob to align a pair of blue/green

together, or to take them out of

alignment. Experiment to see

some interesting effects.

Adding the 0.1mF capacitor lowers the frequency

(pitch) of the sound produced by the green keys,

and makes them similar to the blue keys.

Project 27

Very Low Pitch Keyboard

-32-

Project 29

Keyboard Echo

Project 30

Lower Pitch

Keyboard Echo

Project 31

Optical Keyboard Echo

Project 32

Low Pitch

Optical

Keyboard Echo

Use the preceding

circuit, but add the

0.1mF capacitor

(C2) or the 1mF

capacitor (C7)

across the “CAP”

and “(-)” snaps on

the keyboard using

a 1-snap wire. The

pitch of the green

keys is lower now.

Build the circuit as shown,

and turn on the slide switch

(S1). Press keys on the

keyboard (U26) and hear

the sound with echo on the

speaker (SP2). RV adjusts

the amount of echo, and

RV3 adjusts the volume. Try

this at different RV settings,

because the effects are

very interesting with both

high and low echo amounts.

Build the circuit as shown,

and turn on both slide

switches (S1). Press keys on

the keyboard (U26) or shine

light into the photoresistor

(RP) to hear sound with echo

on the speaker (SP2). RV

adjusts the amount of echo,

and RV3 adjusts the volume.

Wave your hand over the

photoresistor to adjust the

pitch of the “optical” sound.

Try this at different RV

settings, because the effects

are very interesting with both

high and low echo amounts.

There may not be any sound

if there is too much or too

little light on the photo-

resistor.

Use the preceding

circuit, but add the

0.1mF capacitor

(C2) or the 1mF

capacitor (C7)

across the “CAP”

and “(-)” snaps on

the keyboard. The

pitch of the green

keys is lower now.

-33-

In this project you will listen to the keyboard sound both with

and without echo, at the same time (in stereo). This project

requires stereo headphones or a stereo speaker; neither is

included with this set, but this set does include a stereo

cable to help connect to your stereo speaker.

Build the circuit as shown; note that the 5.1kWresistor (R3)

is a tight fit over the adjustable resistor (RV) but does fit.

Connect your own headphones or stereo speaker to the

audio jack (JA). Turn on the slide switch (S1).

Press keys on the keyboard (U26), and listen to the sound

on your headphones or stereo speaker. One ear (or side of

the speaker) hears the keyboard directly, set RV3 for most

comfortable sound level (turn to the left for higher volume,

most of RV3’s range will be very low volume). The other ear

(or side of the speaker) hears the sound with echo; adjust

the amount of echo using the lever on the adjustable resistor

(RV). Try this at different RV settings, because the effects

are very interesting with both high and low echo amounts.

If the echo sound is not loud enough then add the 1mF

capacitor (C7) next the echo IC (U28) as shown here:

For best effects, try to set RV3 so that the sound level is

about equal on both sides of the headphones/speaker.

Headphones or Stereo

Speaker (not included)

WARNING: Headphones performance varies, so use caution. Start with

low volume, then carefully increase to a comfortable level. Permanent

hearing loss may result from long-term exposure to sound at high volumes.

Project 33

The 100Wand 5.1kWresistors (R1 &

R3) make the keyboard signal smaller,

otherwise it would be distorted by the

amplifier in the echo IC.

-34-

Keyboard Echo with

Stereo Effects

Headphones or Stereo

Speaker (not included)

The 0.1mF capacitor (C2) is

being used as a spacer (a

1-snap wire) to support

other components.

WARNING: Headphones performance varies, so use caution. Start with

low volume, then carefully increase to a comfortable level. Permanent

hearing loss may result from long-term exposure to sound at high volumes.

The project is similar to the preceding one, but adds optical

control using the photoresistor (RP). Rebuild the preceding

circuit to match this one. Follow the preceding circuit’s

instructions, except also turn on the slide switch next to the

photoresistor, and then wave your hand over the

photoresistor to change the sound.

The keyboard overhangs the base grid, so be sure the

connections to it stay secure as you are pressing keys.

In the preceding circuit you could add the 1mF capacitor (C7)

to make the echo sound louder, but do not have enough

parts to add it to this circuit.

Build the circuit, turn on the slide switch (S1),

and push the press switch (S2). The color LED

(D8) is on for a while and then shuts off.

Turning S1 off and back on will not get the light

back on. Push S2 to get the light back on. If

desired, place the egg attachment on the color

LED.

RV is used as a fixed resistor (50kW); so

moving its control lever will have no effect.

Project 34

Optical Echo in Stereo

Project 35

Color Short Light

The light is on while the 470mF capacitor

(C5) is charging, and shuts off when the

capacitor gets fully charged. Pressing S2

discharges the capacitor. The charge-up

time is set by the capacitor’s value and

resistors R3 and RV.

-35-

Project 36

Keyboard with Optical Theremin

Project 37

Keyboard with

Optical

Theremin (II)

Project 39

Adjustable Dual

Range Keyboard (II)

Project 40

Adjustable Dual

Range Keyboard (III)

Use the preceding circuit, but replace the

1mF capacitor (C7) with the 470mF

capacitor (C5, “+” on left). You will hear a

click at regular intervals. The interval

depends on the RV setting, it could be

several per second or many seconds apart.

Build the circuit as shown and

turn on the slide switch (S1).

Press keys on the keyboard

(U26) and move the lever on the

adjustable resistor (RV) to

change the sound. Push the

press switch (S2) to change the

pitch of the green keys. There

may not be any sound at some

settings on RV.

Use the preceding circuit, but replace

the 0.1mF capacitor (C2) with the 1mF

capacitor (C7). The pitch of the green

keys is lower when S2 is pressed.

Use the preceding circuit, but

replace the 1mF capacitor (C7) with

the 0.1mF capacitor (C2). The pitch

of the green keys is higher when

S2 is pressed.

Build the circuit as shown and

turn on the slide switch (S1).

Press keys on the keyboard

(U26), wave your hand over the

photoresistor (RP) to adjust the

amount of light shining on it, and

listen to the sound. Push the

press switch (S2) to change the

pitch of the green keys. There

may not be any sound if there is

too much or too little light on the

photoresistor.

Project 38

Adjustable Dual Range Keyboard

-36-

Project 41

Your Music with Echo

MP3 player

Project 42

Your Music with Echo and Light

MP3 player

This circuit is similar to the preceding one, except

it adds light and has lower sound volume. Build the

circuit, and turn on the slide switch (S1). Connect

a music device (not included) to the audio jack (JA)

as shown, and start music on it. Set the knob on

the 500kWadjustable resistor (RV3) all the way to

the left (for loudest sound).

Set the volume control on your music device for a

comfortable sound level, and adjust the amount of

echo using the lever on the adjustable resistor

(RV). Try this at different RV settings. The color

LED (D8) will light when the sound is loud enough.

Try with different music, or with the touch-tones on

your cell phone.

Build the circuit, and turn on the slide switch (S1). Connect

a music device (not included, but this set does include a

cable to connect it) to the audio jack (JA) as shown, and

start music on it.

Set the volume control on your music device for a

comfortable sound level, and adjust the amount of echo

using the lever on the adjustable resistor (RV); move the

lever up for more echo or down for less echo. Try this at

different RV settings, because the effects are very

interesting with both high and low echo amounts.

Try with different music, or with the touch-tones on your cell

phone.

-37-

Use the circuit from project 43,

but replace the 100Wresistor

(R1) with the color LED (D8, “+”

to the left). Now when you press

S2 to play the recording, the

color LED will be flashing.

Project 43

Your Music Speed Changer

MP3 player

Project 44

Your Music

Speed Changer

(II)

Project 46 Sound On Light

Project 45

Your Music

Speed Changer

(III)

Build the circuit as shown. Set the 500kWadjustable resistor

(RV3) to mid-range, turn OFF the left slide switch (S1), and then

turn on the right slide switch. Connect a music device (not

included) to the audio jack (JA) as shown, and start music on it.

Now turn on the left slide switch, you hear a beep signaling that

recording has started. Wait until you hear a beep (signaling that

recording time is over), then turn off the left slide switch to exit

recording mode. Push the press switch (S2) to play back the

recording, and turn the knob on RV3 to change the playback

speed. You can play your recording faster or slower by changing

the setting on RV3. Try with different music, or with the touch-

tones on your cell phone.

To adjust the volume, adjust it on your music device before

recording, or see the next project.

Recording time is 6 seconds at normal speed, but this can be

changed depending on the setting of RV3 when you are making

the recording.

Use the preceding circuit, but

replace the 100Wresistor (R1)

with a 3-snap wire to make the

sound louder, or with the 5.1kW

resistor (R3) to make the sound

quieter.

Build the circuit as shown

and turn on the slide switch

(S1). Set the lever on the

adjustable resistor (RV) so

the color LED (D8) just

shuts off. Talk loudly into the

microphone (X1), blow on it,

or clap near it to make the

LED flicker on.

-38-

Project 47

Super Optical Keyboard Echo

Project 48

Softer Optical

Keyboard

Echo

This circuit is shown on the Snap

Circuits®Sound box cover; use

that picture to help in building it.

Use the preceding circuit, but remove the

1mF capacitor (C7) from the circuit, or

swap it with the 0.1mF capacitor (C2), or

replace it with the 470mF capacitor (C5).

The sound volume is different now.

Build the circuit as shown. Turn off the left slide switch (S1), and

turn on the right slide switch. Press some of the keyboard keys

and listen to the echo. Move the lever on the adjustable resistor

(RV) to change the amount of echo (up is maximum echo, down

is no echo). Try this at different RV settings, because the effects

are very interesting with both high and low echo amounts. The

color LED (D8) will light when any green key is pressed, but will

not be very bright.

Now turn on the left slide switch to add the photoresistor (RP) to

the circuit. Wave your hand over the photoresistor to change the

sound. Try it with different levels of light shining on the

photoresistor, and at different RV settings.

Project 49 Reflection Detector

Build the circuit and turn the

slide switch (S1). Take it

into a dimly lit room, so that

the color LED (D8) is

flashing but there is no

sound.

Now hold a mirror directly

over the color LED and

photoresistor (RP). When

the mirror reflects the LED’s

light into the photoresistor,

a tone will be produced,

signaling that a reflection

was detected. The tone will

change as the LED flashes.

-39-

Project 50

Super Optical

Keyboard Echo for

Headphones

Headphones or Stereo

Speaker (not included)

WARNING: Headphones performance varies, so use caution. Start with

low volume, then carefully increase to a comfortable level. Permanent

hearing loss may result from long-term exposure to sound at high volumes.

Build the circuit as shown. This project requires stereo

headphones or a stereo speaker (neither is included).

Turn off the left slide switch (S1), and turn on the right slide

switch. Press some of the keyboard keys and listen to the

echo. Set the 500kWadjustable resistor (RV3) for most

comfortable sound level (turn to the left for higher volume,

most of RV3’s range will be very low volume). Move the

lever on the adjustable resistor (RV) to change the amount

of echo (up is maximum echo, down is no echo). Try this

at different RV settings, because the effects are very

interesting with both high and low echo amounts. The

color LED (D8) will light when any green key is pressed,

but will not be very bright.

Now turn on the left slide switch to add the photoresistor

(RP) to the circuit. Wave your hand over the photoresistor

to change the sound. Try it with different levels of light

shining on the photoresistor, and at different RV settings.

Note that the “R” snap on the audio jack is not snapped

or connected, so there will not be any sound from the “R”

side of your headphones/speaker.

You can replace the 0.1mF capacitor (C2) with the 1mF

capacitor (C7) to lower the pitch of the green keys.

-40-

Sound is a variation in air pressure created by a mechanical

vibration. For a demonstration of this, take a stereo speaker in

your home (the larger the better), lay it on the floor, and start

some music.

1. Place your hand on your

stereo speaker and turn up

the volume. Do you feel the

speaker vibrate?

2. Now place a piece of paper

on the speaker; if the sound is

loud enough, you will see the

paper vibrate.

3. Take a balloon (not included) and hold

it on the speaker. You should feel it

vibrating with the sound.

Get your parents’ permission for this part,

because it could get messy. Place the

sound energy demonstration container

(which should have been assembled as

per instructions on page 4) on the center

of the speaker. Pour some salt, glitter,

small foam or candy balls (0.1 inch

diameter or less) or similar into the

container, but not enough to cover the

bottom. Slowly increase the music

volume. When the music is at certain

frequencies, the salt/glitter/balls will

bounce around in the container.

Stereo Speaker (not included)

If you have a stereo speaker (not included), then

you can also do the preceding demonstration

using the sounds from your keyboard (U26). Build

the circuit as shown, and connect your stereo

speaker to it. Start with the left slide switch (S1)

turned off and the right switch turned on. Press

keys to find the one that gives the best effects with

the 3 experiments in the preceding project, then

turn the tune knob on the keyboard to see if you

can make the effects even better.

Now turn on the left slide switch to add the

photoresistor (RP) to the circuit. Move your hand

over the photoresistor to adjust how much light

shines into it, to change the sound to give the best

effects for the 3 experiments in the preceding project.

Project 51 Sound is Air Pressure

Project 52 Sound is Air Pressure -

Keyboard

Your Snap Circuits®

speaker (SP2) is not

powerful enough to

use for this, unless

using the sound

energy demonstration

container as done in

project 13.

-41-

Project 53 Brightness Adjuster

Project 54 Brightness

Limiters

Resistors are used to control or limit the flow of electricity in a circuit.

Higher resistor values reduce the flow of electricity in a circuit.

In this circuit, the adjustable resistor is used to adjust the LED brightness,

to limit the current so the batteries last longer, and to protect the LED

from being damaged by the batteries.

What is Resistance? Take your hands and rub them together very fast.

Your hands should feel warm. The friction between your hands converts

your effort into heat. Resistance is the electrical friction between an

electric current and the material it is flowing through.

The adjustable resistor can be set for as low as 200W, or as high as

50,000W(50kW).

Project 55

Vary the brightness of the color

LED (D8) using the 500kW

adjustable resistor (RV3).

Use the preceding circuit, but

replace the 3-snap with one of the

yellow resistors in this set (R1 or

R3). Observe how each changes

the LED brightness at different

settings for the adjustable resistor.

Build the circuit and turn on the slide switch (S1). Move the lever on the

adjustable resistor (RV) to vary the brightness of the light from the color

LED (D8). If desired, you may place the egg LED attachment on the

LED.

Big Brightness

Adjuster

The 500kWadjustable resistor

(RV3) can be set for as low as

200W, or as high as 500,000W

(500kW), so the color LED will

only light on a small portion of

RV3’s range.

The R1 resistor (100W) will have

little effect, because the adjustable

resistor (RV) will always dominate

it. Resistor R3 (5.1kW) will

dominate when RV is set for low

values, but have little effect when

RV is set at high values.

-42-

Photo Brightness

Adjuster

Project 56

Amplified Photo

Brightness

Adjuster

Project 57

Amplified Big

Brightness Adjuster

Project 58

Vary the brightness

of the color LED

(D8) by varying the

amount of light

shining on the

photoresistor (RP).

Vary the brightness of the color LED

(D8) by varying the amount of light

shining on the photoresistor (RP). Notice

that you have to cover the photoresistor

to make the color LED dim.

Some materials, such as Cadmium Sulfide, change their

resistance when light shines on them. Electronic parts made

with these light-sensitive materials are called photoresistors.

Their resistance decreases as the light becomes brighter.

The resistance of your Snap Circuits®photoresistor changes

from nearly infinite in total darkness to about 1kWwhen bright

light shines directly on it. Note that a black plastic case

partially shields the Cadmium Sulfide part.

Photoresistors are used in applications such as streetlamps,

which come on as it gets dark due to night or a severe storm.

In the preceding circuit the photoresistor

directly controlled the current through the

color LED. In this circuit the current

through the photoresistor is amplified by

the NPN transistor (Q2), so the light on

the photoresistor must get very dark

before the color LED brightness is

reduced.

Vary the brightness of the

color LED (D8) using the

500kWadjustable resistor

(RV3). The brightness

won’t change a lot; you

may need to view it in a

dark room to notice the

difference. Placing the egg

attachment on the color

LED may help to notice the

brightness difference.

Compare this circuit to project 55 (Big

Brightness Adjuster). In project 55 the

color LED was dark for most of RV3’s

range. In this circuit the NPN transistor

(Q2) amplifies the current through

RV3, so the color LED is bright for

most of RV3’s range.

-43-

Project 59 Cup & String Communication

How it works: When you talk into the cup, the cup

bottom vibrates back and forth from your sound

waves. The vibrations travel through the string by

pulling the string back and forth, and then make

the bottom of the second cup vibrate just like the

first cup did, producing sound waves that the

listener can hear. If the string is tight, the received

sound waves will be just like the ones sent, and

the listener hears what the talker said.

Telephones work the same way, except that

electric current replaces the string. In radio, the

changing current from a microphone is used to

encode electromagnetic waves sent through the

air, then decoded in a listening receiver.

Cups

String

Pencil

Tiny hole Knot

String threaded

through cup bottom

Taut string

Sound, radio signals, and light all travel through air like waves travel through

water. To help you understand how they are like waves, you can make a cup

& string telephone. This common trick requires some household materials (not

included with this kit): two large plastic or paper cups, some non-stretchable

thread or kite string, and a sharp pencil. Adult supervision is recommended.

Take the cups and punch a tiny hole in the center of the bottom of each with

a sharp pencil (or something similar). Take a piece of string (use between 25

and 100 feet) and thread each end through each hole. Either knot or tape the

string so it cannot go back through the hole when the string is stretched. Now

with two people, have each one take one of the cups and spread apart until

the string is tight. The key is to make the string tight, so it’s best to keep the

string in a straight line. Now if one of you talks into one of the cups while the

other listens, the second person should be able to hear what the first person

says.

-44-

Project 60

MP3 player

Project 61

Low Power

Audio

Amplifier

Project 62

Audio Amplifier with L/R Control

Build the circuit, and turn

on the slide switch (S1).

Connect a music device

(not included) to the audio

jack (JA) as shown, and

start music on it. Set the

volume using the lever on

the adjustable resistor

(RV). This is a simple

amplifier, so the sound

may not be very loud.

Use the preceding circuit, but replace one

of the battery holders (B1) with a 3-snap

wire. The circuit works the same but is not

as loud now.

Build the circuit, and connect the 2-snap wire between the

B1 battery holders last. Connect a music device (not

included) to the audio jack (JA) as shown, and start music

on it. Turn on both of the slide switches (S1), and set the

volume using the lever on the adjustable resistor (RV). This

is a simple amplifier, so the sound may not be very loud.

Turn off either of the slide switches to shut off the left or

right outputs of your music device. If the left and right

outputs of your music signal are the same, then turning off

one switch will reduce the volume a little.

When finished, remove the 2-snap wire between the

battery holders to turn off the circuit.

Audio Amplifier

MP3 player

This circuit does not have an

on/off switch, because the slide

switches are being used to

control the music device outputs.

-45-

Project 63

Your Music without Echo

MP3 player

Project 64

Low Power

Your Music

without

Echo

Here we are using the

amplifier inside the echo

IC (U28), without adding

any echo effects to the

music.

Project 65

Adjustable Music without Echo

MP3 player

Modify the project 63 circuit to include a

volume control, the adjustable resistor

(RV). It works the same way, but adjust the

volume using the lever on RV.

Build the circuit, and turn

on the slide switch (S1).

Connect a music device

(not included, but this set

does include a cable to

connect it) to the audio

jack (JA) as shown, and

start music on it.

Set the volume control on

your music device for a

comfortable sound level. Use the preceding circuit, but

remove the 1mF capacitor

(C7) from the circuit, or

replace it with the 0.1mF

capacitor (C2). The volume is

not as loud now.

-46-

Project 66 L/R Music Amplifier

MP3 player The left and right outputs of

your music device are intended

to control separate speakers,

but are combined here

because you only have one

Snap Circuits®speaker.

This circuit is similar to

project 58 (Amplified Big

Brightness Adjuster), but

the color LED will not be

quite as bright. In this circuit

both the controlling current

(through RV3) and

controlled current (through

R1) also flow through the

color LED, reducing the

amplification.

Vary the brightness of the color LED (D8) using the 500kWadjustable

resistor (RV3).

Build the circuit, and turn on the slide switch (S1).

Connect a music device (not included) to the audio

jack (JA) as shown, and start music on it. Use the

lever on the adjustable resistor (RV) to adjust the

volume for the left and right outputs of your music

device; both won’t be loud at the same time.

Project 67 Another Transistor Amplifier

-47-

Build the circuit, and turn on the slide switch (S1).

The resistance of the 5.1kWresistor (R3) and

microphone (X1) determine the pitch (frequency)

of the tone.

Push the press switch (S2) to bypass the

microphone, and the tone changes.

Build the circuit, and turn on the slide switch (S1).

The color LED (D8) is dimly lit, because the

resistance of the microphone (X1) keeps the

current low.

Push the press switch (S2) to bypass the

microphone, and the LED gets bright.

You can also try replacing the microphone with

the 5.1kWresistor (R3), to see how their

resistances compare.

Project 69

Microphone

Resistance - Audio

Project 68

Microphone

Resistance - LED

The microphone changes resistance when

exposed to changes in air pressure, such as

from sound waves or blowing on it. Talking

into the microphone or blowing on it will

change the LED brightness, but probably not

enough for you to notice the difference.

-48-

Project 70

Time Light

Project 71

Time Light (II)

The 470mF capacitor (C5)

can store electricity. This

timer circuit works by slowly

charging up C5; the color

LED goes out when C5 gets

full. If you replace C5 with C2

or C7, the LED will go out

almost immediately because

these values can’t store

nearly as much electricity.

Use the preceding circuit, but replace the

adjustable resistor (RV) with the 5.1kWresistor

(R3). The circuit works the same way, but the

color LED can only light over a small part of

RV3’s range, and it gets dim faster.

Build the circuit, and turn on the slide

switch (S1). Push the press switch (S2)

and set the 500kWadjustable resistor

(RV3) so the color LED (D8) just comes

on, then release the press switch. The

color LED will be bright for a while and

slowly get dim and go out. Push the press

switch again to reset the color LED’s timer.

You can change RV3’s setting to keep the

color LED on much longer. The adjustable

resistor (RV) is used here as a fixed

resistor (of 50kW), so moving its lever will

have no effect.

Use the preceding circuit, but replace the

adjustable resistor (RV) with the 5.1kWresistor

(R3). The circuit works the same way, but the

color LED gets dim faster.

Project 72

Easier Adjust

Time Light

Build the circuit, and turn on the slide

switch (S1) Push and release the press

switch (S2). Set the 500kWadjustable

resistor (RV3) so the color LED (D8) is on

and bright, then wait for it to get dim and

go out. Push the press switch again to

reset the color LED’s timer. The brighter

the color LED starts, the faster it gets dim.

The adjustable resistor (RV) is used here

as a fixed resistor (of 50kW), so moving its

lever will have no effect.

Project 73

Small Adjust

Time Light

-49-

Project 74

Day Light

Project 75 Lower Day Light

Build the circuit, and turn on the

slide switch (S1). Set the knob on

the 500kWadjustable resistor

(RV3) all the way to the right. If the

room light is bright then the color

LED (D8) should be off. Cover the

photoresistor (RP) or take the

circuit into a dark room, and the

color LED should turn on.

Build the circuit, and turn on the slide switch (S1). Blow into the

microphone (X1), and hear it on the speaker (SP2).

This circuit is like the

preceding one, but

can be used in

darker rooms. Build

the circuit, and turn

on the slide switch

(S1). Set the lever

on the adjustable

resistor (RV) so the

color LED (D8) just

gets bright. Now

when you block the

light to the photo-

resistor (RP), the

color LED will turn

off.

Build the circuit, and

turn on the slide

switch (S1). Set the

lever on the

adjustable resistor

(RV) so the color

LED (D8) just gets

bright. Now when

you block the light to

the photoresistor

(RP), the color LED

will turn off. If the

color LED cannot be

turned on or off at

any RV setting, then

change your room

lighting.

Project 76

Dark Light

Project 77

Blow Noise

-50-

Listen to the

Light Change

Project 78

The color LED actually

contains separate red, green,

and blue lights, with a

microcircuit controlling them.

Each time the LED changes

colors, the voltage across it

changes. Each time the

voltage changes, you hear a

“click” from the speaker.

Project 79

Adjustable Listen to

the Light Change

Project 80

Bright or Loud?

Turn on the slide switch (S1). The color

LED (D8) changes colors in a repeating

pattern, and you hear a clicking sound

from the speaker (SP2).

Turn on the slide switch (S1). Set the

lever on the adjustable resistor (RV) for

different brightness levels on the color

LED (D8). The color LED is bright on a

more limited range of RV settings than

in the preceding project, and the

speaker (SP2) is not nearly as loud.

Now push the press switch (S2); the

LED is dimmer but the sound is louder.

Turn on the slide switch (S1). Set

the lever on the adjustable resistor

(RV) for different brightness levels

on the color LED (D8). You also

hear a clicking sound from the

speaker (SP2).

The transistor (Q2) amplifies the

LED current, to make the speaker

(SP2) sound louder.

When S2 is off the transistor

(Q2) has little effect, and the

circuit is similar to project

46. With S2 pressed, the

transistor acts as an

amplifier, increasing the

current through the speaker.

The LED current is lower in

this arrangement.

-51-

Project 81

LED Keyboard Control

Project 82

LED

Keyboard

Control (II)

Project 83

Photo LED

Keyboard

Control

Use the project 81 circuit, but replace

the 5.1kWresistor (R3) with the

photoresistor (RP). Wave your hand

over the photoresistor or adjust the

room lighting to vary the amount of

light shining on the photoresistor, and

listen to the sounds. You can also

press keys on the keyboard (U26) to

add more sounds.

Build the circuit, and turn on the slide

switch (S1). You hear a sound pattern

that is synchronized with the color LED

(D8) flashing. You can press keys on the

keyboard (U26) to change the sound.

Use the preceding circuit, but

remove the 5.1kWresistor

(R3). Now there is only sound

when you press keys on the

keyboard, and the sounds for

some keys are different.

Modify the project 81 circuit to match

this one. Turn on the slide switch (S1)

and move the lever on the adjustable

resistor (RV) to vary the sounds. You

can also press keys on the keyboard

(U26) to add more sounds.

Project 84

Adjustable

LED Keyboard

Control

The color LED turns off briefly when it

changes colors. Here the color LED

controls the keyboard through the

transistor (Q2), so when the color LED

turns off, the keyboard sound is also

turned off. This produces the sound

effects you hear.

-52-

Build the circuit as shown. Place the circuit in

a quiet room. Connect the speaker (SP2)

using the red & black jumper wires, then hold

it away from the microphone (X1). Turn on the

slide switch (S1). Talk into the microphone or

press keys on the keyboard (U26), and listen

the echo on the speaker. Adjust the volume

using the knob on RV3. Adjust the amount of

echo using the lever on RV; move the lever up

for more echo or down for less echo. Try this

at different RV settings, because the effects

are very interesting with both high and low

echo amounts.

Note: You must hold the speaker away from

the microphone or the circuit may self-oscillate

due to feedback. You also need a quiet room,

with low background noise.

Project 85

Capacitor Keyboard Control

Project 86

Capacitor

Keyboard

Control (II)

Adding the capacitor changes

the range of tones produced

by the keyboard.

Project 87 Voice & Keyboard Echo

Build the circuit, and turn both

slide switches (S1). You hear

a sound pattern that is

synchronized with the color

LED (D8) flashing. Move the

lever on the adjustable

resistor (RV) to change the

sound produced. You can also

press keys on the keyboard

(U26) to change the sound.

Use the preceding circuit, but replace

the 1mF capacitor (C7) with the 0.1mF

capacitor (C2). The sounds are

different now.

-53-

Build the circuit as shown. Place the circuit in a quiet

room. Connect the speaker (SP2) using the red & black

jumper wires, then hold it away from the microphone.

Turn on the slide switch (S1). Talk into the microphone

or press keys on the keyboard (U26), and listen the

echo on the speaker. Adjust the amount of echo using

the lever on the adjustable resistor (RV); move the

lever up for more echo or down for less echo. Try this

at different RV settings, because the effects are very

interesting with both high and low echo amounts.

The color LED (D8) lights when keys are

pressed but will be dim. It is easier to see

in a dimly lit room.

Note: You must hold the speaker away

from the microphone or the circuit may self-

oscillate due to feedback. You also need a

quiet room, with low background noise.

Project 88 LED Voice Keyboard Echo

Project 89

Photo LED

Keyboard

Echo

Project 90

Photo LED

Keyboard

Project 91 Audio Dark Light

Use the preceding circuit, but

remove the adjustable resistor (RV)

from the circuit. Press keys on the

keyboard (U26), and vary the light to

the photoresistor (RP) to adjust the

volume. There won’t be any echo

effects now.

Use the preceding circuit, but

replace the microphone (X1) with the

photoresistor (RP). As you are

pressing keys on the keyboard

(U26), vary the amount of light

shining into the photoresistor to

change the sound. Try it using

different settings on the adjustable

resistor (RV).

Build the circuit, and

turn on the slide

switch (S1). Set the

knob on the 500kW

adjustable resistor

(RV3) to the right

until the color LED

(D8) is off. Cover

the photoresistor

(RP) or take the

circuit into a dark

room, and the color

LED should turn on,

and you hear

clicking from the

speaker (SP2). The

clicking will not be

very loud.

-54-

Project 92

Oscillator

This circuit is an oscillator, because it

produces a repetitive electrical signal on its

own. You hear it as sound waves from the

speaker. The signal is produced by a circuit

inside the keyboard module, but may be

controlled using your Snap Circuits®

resistors and capacitors, and the keys on

the keyboard. The keys are actually

connecting different resistors inside the

keyboard, similar to the 5.1kWresistor (R3).

Project 93

Oscillator (II)

Project 94

Oscillator (III)

Project 95

Oscillator (IV)

Project 96

Oscillator (V)

Use the preceding circuit, but

replace the 1mF capacitor (C7) with

the 0.1mF capacitor (C2). Do you

hear anything? The circuit is

producing a high frequency tone,

which may be too high for your ears

to hear, especially if you are older.

Now remove the 0.1mF capacitor

from the circuit. This makes the

tone even higher frequency, and

you probably won’t hear anything

now. Dogs have better high

frequency hearing, so maybe your

dog can hear it.

Use the preceding circuit, but replace

the 5.1kW resistor (R3) with the 100W

resistor (R1). The frequency of the

sound is higher now, and you hear

several clicks a second.

Use the preceding circuit, but replace

the 470mF capacitor (C5) with the 1mF

capacitor (C7). The frequency of the

sound is much higher now, and you hear

a continuous tone.

Use the preceding circuit, but replace

the 1mF capacitor (C7) with the 470mF

capacitor (C5). The frequency of the

sound is now so low that you just hear

a click every few seconds.

Use the preceding circuit, but replace

the 0.1mF capacitor (C2) with the 1mF

capacitor (C7). The frequency (pitch)

of the sound is lower now.

Build the circuit, and turn the slide switch

(S1). You hear a tone. You can also press

keys on the keyboard (U26) to change the

sound.

Project 98

Left Right Bright Light

Turn on the slide switch

(S1) and move the

lever on the adjustable

resistor (RV) around.

The color LED (D8) is

bright if the lever is to

the far left or far right,

and dim if the lever is in

the middle.

Project 97

Oscillator (VI)

-55-

Project 99

Adjustable Oscillator

Project 100

Adjustable

Oscillator

(II)

Project 101

Adjustable

Oscillator

(III)

Project 102

Adjustable

Oscillator

(IV)

Project 103 Water Detector

Use the preceding circuit, but

remove the 470mF capacitor

(C5) from the circuit. See the

range of sounds that this

circuit can produce.

Use the preceding circuit, but

replace the 1mF capacitor (C7)

with the 470mF capacitor (C5).

You can hear a clicking sound

for a small part of RV3’s

adjustment range.

Use the preceding circuit, but

replace the 0.1mF capacitor

(C2) with the 1mF capacitor

(C7). The frequency (pitch) of

the sound is lower now.

Build the circuit, and turn the slide switch

(S1). Turn the knob on the 500kW

adjustable resistor (RV3) to see the range

of sounds that can be produced; there will

only be sound for a small part of RV3’s

range. You can also press keys on the

keyboard (U26) to change the sound.

Build the circuit, and

initially leave the loose

ends of the red &

black jumper wires

unconnected. Turn on

the slide switch (S1);

nothing happens. Now

place the loose ends

of the red & black

jumper wires into a

cup of water, without

their snaps touching

each other. The color

LED (D8) should be

on now, indicating that

you have detected

water!

RV’s 500kWadjustment

range is wide, and the

oscillator circuit inside

the keyboard (U26)

won’t function over RV’s

full range. At some

settings the circuit may

function, but produce too

high of frequency for

your ears to hear.

-56-

Project 104

Clicker

The color LED turns off briefly when

it changes colors. What you hear in

the speaker is the change in current

as the LED turns on or off.

Build the circuit, and turn the slide switch (S1). The color LED (D8) is

flashing, and you hear a clicking sound.

Modify the preceding circuit to be this one, which adds echo effects.

Turn on the slide switch (S1) and push the press switch (S2) to see the

color LED (D8) flashing and hear a clicking sound. When you release

the press switch, the color LED shuts off but you hear echo effects. Use

the lever on the adjustable resistor (RV) to set the echo level.

Project 105

Clicker with Echo

-57-

Project 106

3V Audio Amplifier

MP3 player

Build the circuit as shown, and place it in a quiet room.

Connect the speaker (SP2) using the red & black jumper

wires, then hold it away from the microphone (X1). Turn on

the slide switch (S1). Talk into the microphone, and listen the

echo on the speaker, and see it on the color LED (D8). Adjust

the amount of echo using the lever on the adjustable resistor

(RV); move the lever up for more echo or down for less echo.

Try this at different RV settings. You may need to talk loud

directly into the microphone to make the color LED bright.

Note: You must hold the speaker away from the microphone

or the circuit may self-oscillate due to feedback. You also

need a quiet room, with low background noise.

Build the circuit, and turn on the

slide switch (S1). Connect a

music device (not included) to the

audio jack (JA) as shown, and

start music on it. Turn the knob

on the 500kWadjustable resistor

(RV3) to adjust the volume.

Project 107

Mini Music Player

To demonstrate how much the transistor was

amplifying the sound, connect the speaker

directly to the audio jack, as shown here, and

start music on your music device. If you don’t

hear anything then hold the speaker next to

your ear, or set the volume control on your

music device higher.

MP3 player

Project 108

Voice Echo with Light

The transistor (Q2) amplifies the

current from your music device, to

make the sound louder. The

resistors (R1 & RV3) and

capacitors (C5 & C7) condition

the signal to minimize distortion.

-58-

Use the preceding circuit, but add the 0.1mF

capacitor (C2) over the keyboard (U26)

using a 1-snap wire, as shown. Press a blue

and a green key at the same time, while

turning the TUNE knob.

Watch the colors on the color

LED (D8), and listen to the

sound. Normally the color LED doesn’t work

when you connect it backwards, but in

this circuit it does. The changing

voltage produced by the keyboard

actually goes both ways (positive and

negative), so here the color LED will

work in either direction.

Project 112

Backwards Color

Sound

Use any of the 3 preceding circuits, but reverse the

direction of the color LED (D8). The circuit works the

same, but the sound may not be as loud and the LED

may not be as bright.

Use the preceding circuit, but use the 1mF

capacitor (C7) instead of the 0.1mF capacitor

(C2). Press a blue and a green key at the

same time, while turning the TUNE knob.

Watch the colors on the color LED (D8), and

listen to the sound.

Next, replace the 1mF capacitor (C7) instead

of the 470mF capacitor (C5). Press one of

the green keys and hold it down. Every few

seconds, the color LED flashes and you hear

a click from the speaker.

Build the circuit and turn the slide switch

(S1). Press any key on the keyboard

(U26), but just one key at a time. The

color LED (D8) lights (mostly red), and

you hear a tone from the speaker (SP2).

Now press one blue key and one green

key at the same time, to produce 2

tones on the speaker. Watch the color

LED (D8) closely; you should see more

green and blue color than before. Try

viewing it in a dimly lit room.

Now turn the TUNE knob while pressing

the blue C key and the green C key at

the same time. Slowly turn the knob

across its entire range, and see how the

LED color changes.

The spectrum of LED color here

depends on your batteries. With strong

batteries you will see more green and

blue. With weak batteries you will mostly

see red.

Project 109

Color Sound

Normally the color LED changes colors, but here

it doesn’t, why? The U26 keyboard produces a

changing voltage, intended to produce sound on

the speaker. The color LED is designed for use

with a stable voltage (like the batteries); when

used with the changing voltage from the

keyboard, it gets confused and blurs its pattern.

Red is the easiest color for the color LED to

produce, and blue is the hardest. So when the

voltage to it is weak, the more difficult colors get

dim first.

The keyboard produces separate tones for the

blue and green keys, which are played together

at the speaker. The two tones are also control

the color LED. When the tones combine, it is

easier for the color LED to produce green and

blue color.

Project 111

Color Sound (III)

Project 110

Color Sound (II)

-59-

The color LED actually contains separate red, green,

and blue LED controlled by a microcircuit. It is designed

for use with a stable voltage (like the batteries); when

used with the keyboard output (a changing voltage

intended to produce sound on the speaker), it gets

confused and blurs its pattern. The result appears white

because mixing equal amounts of red, green, and blue

light makes white light.

Project 114 Red to White

RV3 controls the voltage

to the color LED, through

transistor Q2. When the

voltage is low, the color

LED only produces red,

since that is the easiest

color for it to produce. As

the voltage increases,

green light is added, then

blue.

Build the circuit and turn the slide switch (S1). Press any key on the

keyboard (U26), but just one key at a time. The color LED appears

white, and isn’t changing colors like it normally does. If you look closely

at the color LED you can see separate red, green, and blue lights on it,

which combine to produce white. This is best seen in a dark room. You

can also view it with the egg attachment on the color LED, which helps

to blend the LED colors together.

Use the preceding circuit, but replace the 5.1kWresistor (R3) with

the 500kWadjustable resistor (RV3). Press any key on the keyboard

(U26), but just one key at a time. Slowly turn the knob on RV3 from

right to left across its range while watching the color LED (D8)

closely. Notice how first red gets bright, then green too, then also

blue. This is best seen in a dark room. You can also try it with the

egg attachment on the color LED.

Build the circuit with the black jumper wire connected as shown, and turn it on.

Nothing happens. Disconnect the jumper wire and an alarm sounds.

Project 113

White Light

Project 115 Alarm

You could replace

the jumper wire with

a longer wire and

run it across a

doorway to signal an

alarm when some-

one enters.

-60-

Project 120

Knob Echo

Project 116

Super Voice Echo with Light

Project 117

Press Echo

Project 118

Photo Echo

Build the circuit as shown,

turn on the slide switch (S1),

and turn the knob on the

500kWadjustable resistor

(RV3). You hear clicking in the

speaker (SP2), and the color

LED (D8) flashes. Adjust the

amount of echo using the

lever on the adjustable

resistor (RV). Try this at

different RV settings.

If you remove the speaker

(SP2) from the circuit then the

color LED (D8) will be a little

brighter, because the echo IC

(U28) isn’t trying to control the

speaker at the same time.

Use the preceding circuit, but

replace the microphone (X1)

with the press switch (S2).

Set RV3 to max volume (turn

it to the left). Press S2 to see

light on the color LED (D8),

and hear a clicking sound

from the speaker (SP2).

Build the circuit as shown, and turn on

the slide switch (S1). Talk into the

microphone, and listen the echo on the

speaker, and see it on the color LED

(D8). Set the sound volume using the

knob on the 500kWadjustable resistor

(RV3). Adjust the amount of echo using

the lever on the adjustable resistor

(RV).

Note: There will only be sound if RV3

is set towards the left (most of its range

will have no sound). Also, at the loudest

RV3 setting the circuit may oscillate

and make a whining sound; just set the

RV3 volume a little lower to stop it.

Use the preceding circuit, but replace the press

switch (S2) with the photoresistor (RP), Adjust

the amount of light shining on the photoresistor

to change the sound and light.

Use the circuit from project 117 (with S2) or 118

(with RP), but replace RV3 with a 3-snap wire. The

sound will be louder but the light will be dimmer.

Project 119

Loud Press

Photo Echo

-61-

Project 121

Echo Light Headphone

Project 122

Echo Light

Headphone Variants

Headphones

(not included)

WARNING: Headphones performance varies, so use caution. Start with

low volume, then carefully increase to a comfortable level. Permanent

hearing loss may result from long-term exposure to sound at high volumes.

Project 123

Press Echo Light

Project 124

Photo Echo Light

Use the preceding circuit, but

replace the press switch with the

photoresistor (RP). Adjust the

amount of light shining on the

photoresistor to change the sound

and light. You may need a big

difference in brightness to notice

the effects.

Next, replace the photoresistor with

the microphone (connect the “+”

side to the echo IC (U28)). Talk

loudly directly into the microphone

to flash the light and hear your

voice on the speaker (SP2), but

your voice will be badly distorted.

Build the circuit as shown, and

turn on the slide switch (S1).

Push the press switch (S2) to

see light on the color LED (D8),

and hear a clicking sound from

the speaker (SP2). Adjust the

amount of echo using the lever

on the adjustable resistor (RV).

Use the preceding circuit, but

replace the microphone (X1) with

the press switch (S2). Press S2 to

see light on the color LED (D8),

and hear a clicking sound from

your headphones.

Next, replace the press switch with the

photoresistor (RP), Adjust the amount

of light shining on the photoresistor to

change the sound and light.

You can use a stereo speaker (not

included) instead of headphones.

When using it with the microphone

(X1), you may need to lower the

volume to prevent feedback into

the microphone.

Build the circuit as shown, and connect your

own headphones (not included) to the audio

jack (JA). Turn on the slide switch (S1).

Talk into the microphone, and listen the

echo on your headphones, and see it on

the color LED (D8). Set the 500kW

adjustable resistor (RV3) for most

comfortable sound level (turn to the left for

higher volume, most of RV3’s range will be

very low volume); then adjust the amount

of echo using the lever on the adjustable

resistor (RV). Only the left side of your

headphones will have sound.

-62-

Project 126

Daylight Voice Echo

Note that there is a 4-snap wire under Q2, partially hidden. Place the circuit in a quiet

room with bright light shining into the photoresistor (RP). Connect the speaker (SP2)

using the red & black jumper wires, then hold it away from the microphone (X1). Turn

on the slide switch (S1). If the speaker makes a whining sound that does not stop, then

you need brighter light on the photoresistor, or the room is too noisy.

Talk into the microphone, and listen the echo on the speaker. Now block the light to the

photoresistor to turn off the circuit; slowly wave your hand over it to turn the echo on and

off. You can adjust the amount of echo using the lever on the adjustable resistor (RV).

Build the circuit as shown, and turn on the slide switch (S1). Talk into the

microphone (X1) to light the color LED (D8) and hear your voice on the speaker

(SP2). Adjust the amount of echo using the lever on the adjustable resistor

(RV).

Next, replace the microphone with the press switch (S2). Push the press switch

to see light on the color LED, and hear a clicking sound from the speaker.

Project 125

Another Voice Echo Light

The photoresistor controls power to

the echo IC (U28), and acts as an

on/off switch. If there is some light on

it but not bright light, it may only

partially turn on the echo IC, causing

the echo IC to malfunction.

Also, you must hold the speaker

away from the microphone or the

circuit may self-oscillate due to

feedback. You also need a quiet

room, with low background noise.

-63-

Project 127

Dark Voice Echo

Project 128 Project 129

Dark Echo

Variants

Use either of the preceding two

circuits, but replace the microphone

(X1) with the press switch (S2) or

500kWadjustable resistor (RV3). Press

S2 or turn the knob on RV3 to change

the sound or light.

Modify the preceding circuit to match this

one; it uses the color LED (D8) instead of

the speaker (SP2). Turn on the slide switch

(S1); nothing will happen unless the room is

dark. This circuit only works if there is no

light on the photoresistor (RP).

Cover the photoresistor, talk into the

microphone, and see the light flash. You can

adjust the amount of echo using the lever

on the adjustable resistor (RV). Shine light

on the photoresistor to shut off the circuit.

If the color LED never turns off, then you

need to block light from the photoresistor

better.

Build the circuit as shown, and place it in

a quiet room. Connect the speaker (SP2)

using the red & black jumper wires, then

hold it away from the microphone (X1).

Turn on the slide switch (S1); nothing will

happen unless the room is dark. This

circuit only works if there is no light on the

photoresistor (RP).

Cover the photoresistor, talk into the

microphone, and listen the echo on the

speaker. You can adjust the amount of

echo using the lever on the adjustable

resistor (RV). Shine light on the

photoresistor to shut off the circuit.

If the speaker makes a whining sound that does

not stop, then you need to block light from the

photoresistor better, or the room is too noisy.

The photoresistor controls power to the

echo IC (U28), and acts as an on/off switch.

If the photoresistor is not dark enough, it

may only partially turn on the echo IC,

causing the echo IC to malfunction.

Also, you must hold the speaker away from

the microphone or the circuit may self-

oscillate due to feedback. You also need a

quiet room, with low background noise.

Dark Echo Light

-64-

Project 130

Day Echo Light

Project 131

Day Echo

Variants

Project 132

Photo Light Timer

Build the circuit, and turn

on the slide switch (S1). If

there is light on the

photoresistor (RP) then

the color LED (D8) will be

on. Block the light to the

photo-resistor, and the

color LED should slowly

get dimmer and dimmer.

Use the preceding circuit, but replace the

microphone (X1) with the press switch (S2)

or 500kWadjustable resistor (RV3). Press

S2 or turn the knob on RV3 to change the

light.

You can also replace the color LED (D8)

with the speaker (SP2). When used with the

microphone, you must connect the speaker

using the red & black jumper wires and hold

it away from the microphone, and also omit

C7.

Build the circuit as shown, and

place it where there is bright light

shining into the photoresistor

(RP). Turn on the slide switch

(S1). If the color LED never

turns off, then you need brighter

light on the photoresistor.

Talk into the microphone, and

see the color LED (D8) flash.

Now block the light to the

photoresistor to turn off the

circuit; slowly wave your hand

over it to turn the echo on and off

while talking. You can adjust the

amount of echo using the lever

on the adjustable resistor (RV).

Project 133

Adjustable Photo Light Timer

This circuit is similar to the

preceding one, except the color

LED (D8) stays on longer when

you block the light to the

photoresistor (RP). Use the lever

on the adjustable resistor (RV) to

set how long the color LED will

stay bright after the photoresistor

is covered.

The 470mF capacitor (C5)

stores up some electricity,

and releases it when you

block the light.

The resistance of RV

slows down the dis-

charging of the 470mF

capacitor (C5).

-65-

Project 135

Tone Stoppers (II)

The sound is a little

louder now because

the larger 1mF

capacitor passes

more of the tone

than the smaller

0.1mF capacitor did.

Project 136

Tone Stoppers (III)

The sound is much louder now because

the larger 470mF capacitor passes

much more of the tone than the smaller

1mF capacitor did. Now pressing S2

does not increase the sound, because

C5 is already passing all of it.

C7 will give less change on

high frequency tones than

on low frequency tones; you

should be able to notice the

difference as you vary the

tone using RV3. The smaller

C2 will affect both high and

low tones a lot. The larger

C5 will have little effect on

both high and low tones.

Use the circuit from project 135 (with the 1mF capacitor (C7)), but

add the 500kWadjustable resistor (RV3) as shown here. Slowly

turn RV3’s knob to vary the pitch (frequency) of the tone from

lowest to highest possible (there will only be sound for a small

part of RV3’s range). At the same time, press S2 on and off

several times, to see how C7 is changing on the sound.

Next, replace C7 with smaller C2 or larger C5, and compare the

capacitor’s effect as you vary the tone frequency.

Use the preceding circuit, but replace

the 1mF capacitor (C7) with the much

larger 470mF capacitor (C5). Compare

the sound volume to the preceding

circuits. How much difference does

pressing S2 make now?

Use the preceding circuit, but replace

the 0.1mF capacitor (C2) with the

larger 1mF capacitor (C7). Compare

the sound volume to the preceding

circuit.

Build the circuit and turn the slide switch (S1). Press any key on the

keyboard (U26). You hear a tone from the speaker (SP2), though it may

not be very loud.

Now push the press switch (S2) while pressing the same key. The

sound is louder now, because the press switch bypassed the 0.1mF

capacitor.

Project 134

Tone Stoppers

Capacitors can store electricity in small amounts. This

storage ability allows them to block stable electrical signals

and pass changing ones, making them useful in filtering and

delay circuits. Capacitors with higher values have more

storage capacity, and can pass changing signals more easily,

In this circuit the 0.1mF capacitor blocks most of the keyboard

tone signal. You can hear the difference when you press S2

to bypass the capacitor.

Project 137

Tone Stoppers (IV)

-66-

Project 138 Tone Stoppers (V)

Project 140

Voice Changer with Headphones

WARNING: Headphones performance varies, so use caution. Start with

low volume, then carefully increase to a comfortable level. Permanent

hearing loss may result from long-term exposure to sound at high volumes.

Headphones or Stereo Speaker (not included)

This project requires stereo headphones or a stereo speaker (neither

included); connect them to the audio jack (JA). Set the 500kWadjustable

resistor (RV3) to mid-range. Turn on both slide switches (S1), you hear a

beep signaing that you may begin recording. Talk into the microphone until

you hear a beep (signaling that recording time is over), then turn off the left

slide switch to exit recording mode. Push the press switch (S2) to play back

the recording and flash the color LED (D8), and turn the knob on RV3 to

change the playback speed. You can play your recording faster or slower by

changing the setting on RV3.

Adjust the volume to your headphones or stereo speaker using the lever on

the adjustable resistor (RV).

Recording time is 6 seconds at normal speed, but this can be changed

depending on the setting of RV3 when you are making the recording.

In project 137, there is only sound for

a small part of RV3’s range, which

can be difficult to tune. To help,

modify the circuit to add the

adjustable resistor (RV) in series with

RV3, as shown. Slowly adjust RV

and RV3 to vary the tone from lowest

to highest possible, while pressing

S2 on and off, to see how the

capacitors (C7, or C2 or C5) change

the sound.

You can also replace RV3 with the

photoresistor (RP). Set RV to the left,

and then adjust the tone by varying

the light to RP, while comparing the

effects of the capacitors.

Build the circuit with the black

jumper wire connected as

shown, and turn it on.

Nothing happens. Disconnect

the jumper wire and the color

LED (D8) comes on,

signalling an alarm.

RV is more

sensitive and can

be adjusted from

200Wto 50kW,

compared to

200Wto 500kW

for RV3.

Project 139 Alarm Light

-67-

Build the circuit (note that there is a 4-snap wire under Q2, partially

hidden) and turn the slide switch (S1). Press any key on the keyboard

(U26) and set the 500kWadjustable resistor so the sound just shuts off.

Now block the light to the photoresistor (RP) and press some keys to

play tones.

Build the circuit (note that there is a 4-snap wire under Q2, partially

hidden) and turn the slide switch (S1). Press keys on the keyboard

(U26). This keyboard only works during the day, so you have to have

light on the photoresistor or there won’t be any sound. If you cover the

photoresistor or place the circuit in a dark room then it won’t work. If the

light is dim then the sound may be abnormal.

Project 141

Day Keyboard

Project 142

Night Keyboard

-68-

Build the circuit and turn the slide switch (S1). Press and hold down any

green key on the keyboard (U26), and see what happens.

Project 143

Color Keyboard

Project 145

Color Keyboard (III)

-69-

Project 144 Color Keyboard (II)

Modify the preceding circuit by

adding the adjustable resistor

(RV) as shown here. Turn the

slide switch (S1). Move the lever

on the adjustable resistor around;

best effects are when it is to the

left. Press keys on the keyboard

(U26) at the same time. You will

see some cool effects.

Build the circuit and turn the slide switch (S1). Press and hold down any

green key on the keyboard (U26), and see what happens.

Project 146 Color Keyboard (IV)

Modify the preceding circuit by

adding the 100Wresistor (R1) and

replacing the 1mF capacitor (C7)

with the 470mF capacitor (C5), as

shown here. Turn the slide switch

(S1) to see some cool effects.

Press any of the blue keys for

more effects. Pressing the green

keys won’t do anything.

-70-

Project 147

Color Keyboard (V)

Project 148

Color Keyboard

(VI)

Project 149

Adjustable Voice Changer & Light

Project 150

Adjustable

Voice

Changer &

Light (II)

Use the preceding

circuit, but swap the

locations of the speaker

(SP2) and color LED

(D8). Now the color

LED is at full brightness

during playback, and

RV adjusts the sound

volume.

Set the 500kWadjustable resistor (RV3) to mid-

range. Turn on both slide switches (S1), you hear

a beep signaling that you may begin recording.

Talk into the microphone until you hear a beep

(signaling that recording time is over), then turn

off the left slide switch to exit recording mode.

Push the press switch (S2) to play back the

recording, and turn the knob on RV3 to change

the playback speed. You can play your recording

faster or slower by changing the setting on RV3.

Move the lever on the adjustable resistor (RV) to

change the brightness of the color LED (LED)

during playback. Most of RV’s range will give little

or no LED brightness.

Recording time is 6 seconds at normal speed, but

this can be changed depending on the setting of

RV3 when you are making the recording.

Use the preceding circuit, but replace the

1mF capacitor (C7) with the 0.1mF capacitor

(C2). The sound is a little different now, and

the green keys can change it.

Turn on the slide switch (S1).

Move the lever on the

adjustable resistor (RV) around

near the left (not the middle or

right). Press any of the blue

keys for more effects. Pressing

the green keys may not do

anything.

Build the circuit and turn the slide switch (S1). Push the press switch

(S2) and play keys on the keyboard (U26). Play fast, because this

keyboard will only work for a few seconds! Push S2 again to restart the

keyboard and its timer.

Turn on the slide switch (S1). Set the lever on

the adjustable resistor (RV) all the way to the

left. The color LED (D8) should be on, but may

be mostly red. Slowly move the lever on RV to

the right until the LED is completely off. Notice

that the red color stays on the longest.

Now push the press switch (S2) and adjust RV

again, watching the LED colors. Blue and green

color may also appear now, but may go dim

before red does.

Now move S1 from the points marked C & D to

the points marked A & B. Move RV’s lever

around again, watching the LED colors and

brightness. Try pushing S2 again, but it won’t

make as much difference now.

Project 151

Play Fast

Project 152

Red First

The voltage needed to turn on an LED

depends on the light color. Red needs the

least voltage, and blue needs the most.

With S1 at points C & D and S2 off, the

voltage to the color LED is lowest, and may

barely be enough to turn on the red color.

Pressing S2 bypasses the NPN transistor

(Q2), and boosts the LED voltage a little.

Shifting S1 to points A & B increases the

circuit voltage from 3V to 6V, making the

LED work for a greater part of RV’s range.

-71-

Project 153 Adjustable Timer Tone Project 154

Photo Timer

Tone

Note that there is a 3-snap wire

under Q2, partially hidden. Turn

on both slide switches (S1) and

push the press switch (S2). You

hear a tone, which turns off after

a while. Push S2 again to restart

the keyboard and its timer. Use

the adjustable resistor (RV) to set

how long the timer keeps the

sound on for, it can be set for a

few seconds or very long. You

can change the tone that plays by

pressing keys on the keyboard

(U26).

Turning off the left slide switch

turns off the tone, but not the keys

or timer.

Use the preceding circuit, but replace

the 5.1kWresistor (R3) with the

photoresistor (RP). The circuit works

the same way, but you can vary the

pitch of the tone by adjusting the

amount of light on the photoresistor.

Project 156

Adjustable

Delay Lamp

Use the preceding circuit, but replace

adjustable resistor (RV) with the

500kWadjustable resistor (RV3). Set

the knob on RV3 to different positions,

press S2 to start the timer, and see

how long it takes for the color LED to

turn on. Turning RV3’s knob clockwise

gives longer delay, turning counter

clockwise gives shorter delay.

Project 155 Delay Lamp

Push and release the press switch (S2), then turn on the

slide switch (S1). Nothing happens at first, but after a few

seconds the color LED (D8) turns on. Press S2 to turn off D8

and reset the delay timer.

The adjustable resistor (RV) is used as a fixed resistor, and

moving its lever won’t have any effect.

This circuit works because capacitor C5

can store electricity. When you turn on the

circuit, electricity flows through resistor RV

into C5. When C5 gets full, electricity starts

flowing into transistor Q2, which turns on

the color LED. Pressing S2 empties C5,

and resets the timer. Capacitors C2 and

C7 also store electricity, but only small

amounts; if used in this circuit they would

appear to fill up instantly.

RV3 controls how fast electricity flows

into capacitor C5. Increasing RV3’s

value makes it take longer to charge

up C5.

-72-

Turn on both slide switches (S1). Move the lever on

the adjustable resistor (RV) all the way to the left or

right, and watch the brightness of the color LED (D8).

The light should be a little brighter when RV’s lever is

to the left.

Now move RV’s lever toward one side, but not all the

way. There should be a larger difference between the

same positions on the left compared to the right.

Project 158

Continuity

Tester

Use the preceding circuit,

but instead connect the

loose ends of the jumper

wires to different

materials in your home. If

you hear sound, then the

material you tested has

low resistance and is a

good conductor of

electricity.

Project 159

High Low Light

The left side of RV is connected to 6V, while

the right side is only connected to 3V; so the

color LED will be brighter when RV’s lever

is to the left. Moving the lever toward the

middle increases the resistance in the

circuit, and the higher voltage left side will

be less affected than the right side.

Project 157 Water Alarm

Build the circuit, and initially leave the loose

ends of the red & black jumper wires

unconnected. Turn on the slide switch (S1);

nothing happens. Now place the loose ends

of the red & black jumper wires into a cup of

water, without their snaps touching each

other. You should hear a tone now, indicating

that you have detected water!

Don’t drink any water used here.

You could place this circuit

in your basement, then it will

sound an alarm if your

basement starts to flood

during a storm.

-73-

Project 161

Fast Flicker

Clicker

Turn on the slide switch

(S1). Move the lever on

the adjustable resistor

(RV) around to make the

color LED (D8) flicker and

make clicking or buzzing

on the speaker (SP2).

Press keys on the

keyboard (U26) for more

fun effects. Try pressing a

blue key and a green key

at the same time, while

moving RV’s lever

around.

Use the preceding circuit, but replace the

1mF capacitor (C7) with the smaller 0.1mF

capacitor (C2). It works the same way, but

the tone has higher pitch, and the color

LED may appear to be on continuously.

Project 162

Slow Flicker

Clicker

Use the preceding circuit, but

replace the 1mF capacitor (C7)

with the larger 470mF capacitor

(C5). With RV set to the left,

the LED flashes and the

speaker clicks about once a

second. As you move RV’s

lever toward the right, the time

between flashes/clicks

increases and can get very

long. Also try holding down one

of the blue keys; best effects

are when RV is set toward the

left.

Turn on the slide switch (S1) and

push the press switch (S2). You

should hear a tone; adjust its pitch

using the adjustable resistor (RV).

The tone shuts off after about 10

seconds. Push S2 again to re-start

the keyboard and its timer.

Some settings on RV may not

produce any sound. Press S2 and

set RV to where you hear sound.

Project 160 Flicker Clicker

If the speaker is buzzing

and the color LED is on

but not flashing, then the

color LED is probably

flashing so fast that it just

appears as a blur.

Project 163 Timer Tone

-74-

Project 164

Little Battery

Set the knob on the 500kWadjustable resistor (RV3) to the

left. Place the color LED (D8) across the points marked B &

C (“+” to B); the LED lights as the capacitor charges. Next,

place the color LED across points A & B (“+” to A) instead;

now the LED lights as the capacitor discharges. Move the

color LED back to B & C and repeat. Use the knob on RV3

to vary the charge / discharge rate, but keep it close to the

left (otherwise the LED would be too dim to see).

The capacitor is storing energy like a little battery.

Project 165

Tiny Battery

Use the preceding circuit, but

replace the 470mF capacitor (C5)

with the smaller 1mF capacitor

(C7). Set RV3 all the way to the

left. Place the color LED across B

& C to charge C7, then across A

& B to discharge it. The LED will

only flash for a moment, because

C7 can’t store much electricity

(C5 holds 470 times more). The

LED is easier to see in a dimly lit

room.

Set the knob on the 500kWadjustable

resistor (RV3) to mid-range. Place the

470mF capacitor (C5) across the

points marked B & C (“+” to C), then

SWING its “+” side around to point A

(without unsnapping it from point B).

Swing its “+” side between points C &

A several times.

When the capacitor (C5) touches point

C, the color LED (D8) flashes to show

that the batteries charged up the

capacitor. When the capacitor touches

point A, you hear beep from the

speaker (SP2) to show that the audio

circuit discharged the capacitor.

You can change the “beep” sound a

little by turning the knob on RV3.

Batteries can hold a lot

more electricity than

capacitors because

batteries store chemical

energy while capacitors

store electrical energy.

Project 166

Little Battery Beep

The capacitor is storing

energy like a little battery.

The “beep” you hear is the

voice changer (U27) entering

recording mode, but you

can’t make any recording

with this circuit. Capacitor C5

can’t store enough electricity

to operate the voice changer

circuit, but it can power it long

enough to make a beep.

-75-

Project 168

Capacitors

in Series (II)

Turn on the right slide switch (S1). Press

any green key and compare the sound with

the left slide switch on or off.

With the left switch off, the 0.1mF and 1mF

capacitors (C2 & C7) are connected in

series. Turning on the left switch bypasses

the 0.1mF capacitor. Notice that having the

0.1mF included has a big effect on the tone.

Use the preceding circuit,

but swap the locations of

the 0.1mF and 1mF

capacitors (C2 & C7).

Press any green key and

compare the sound with the

left slide switch on or off.

The tone does not

change nearly as much

as in the preceding

circuit. When capacitors

are connected in series,

the smaller value

dominates the circuit.

Use the project 167 circuit, but replace the 0.1mF

capacitor (C2) with the much larger 470mF

capacitor (C5). Press any green key and compare

the sound with the left slide switch on or off.

Now the tone is the same whether the left switch

is on of off, because connecting the large 470mF

in series with the small 1mF has little effect on the

total capacitance.

Swap the locations of the 1mF and 470mF

capacitors (C7 & C5). Press any green key and

compare the sound with the left slide switch on or

off (When the switch is off, hold down the key,

because you will only hear a click every few

seconds.) Now turning on the left switch has a big

effect on the circuit, because connecting the small

1mF in series with the large 470mF greatly

increases the total capacitance.

Turn on the right slide

switch (S1). Press any

green key and

compare the sound

when you remove one

or two of the capacitors

(C2, C5, and C7) and

replace them with a 3-

snap wire. You will only

hear a click every few

seconds if C5 is the

only one in the circuit.

Project 170

More Capacitors in Series

Project 169

Capacitors in Series (III)

Project 167

Capacitors in Series

Think of capacitors as

storage tanks for electricity.

If you place a small storage

tank in series with a big

one, electricity flows into

both at the same time, but

the small one fills up

quickly and stops the flow.

-76-

Project 171

Capacitors in Parallel

Project 172

Capacitors in

Parallel (II)

Turn on the right slide switch (S1). Press

any green key and compare the sound with

the left slide switch on or off.

With the left switch on, the 0.1mF and 1mF

capacitors (C2 & C7) are connected in

parallel. Turning off the left switch

disconnects the 0.1mF capacitor. Notice that

having the 0.1mF included has only a small

effect on the tone.

Use the preceding

circuit, but swap the

locations of the 0.1mF

and 1mF capacitors (C2

& C7). Press any green

key and compare the

sound with the left slide

switch on or off.

The tone changes

much more now than in

the preceding circuit.

When capacitors are

connected in parallel,

the larger value

dominates the circuit.

Think of capacitors as

storage tanks for electricity. If

you place a large storage

tank in parallel with a big one,

electricity flows into both at

the same time, but keeps

flowing until both are full.

Use the project 171 circuit, but replace the 0.1mF

capacitor (C2) with the much larger 470mF capacitor

(C5). Press any green key and compare the sound

with the left slide switch on or off. (When the switch is

on, hold down the key, because you will only hear a

click every few seconds.)

Turning on the left switch has a big effect on the circuit,

because connecting the large 470mF in parallel with

the small 1mF greatly increases the total capacitance.

Swap the locations of the 1mF and 470mF capacitors

(C7 & C5). Press any green key and compare the

sound with the left slide switch on or off. Now the tone

is the same whether the left switch is on of off,

because connecting the small 1mF in parallel with the

large 470mF has little effect on the total capacitance.

Turn on the right

slide switch (S1).

Press any green

key and compare

the sound when

you remove one

or two of the

capacitors (C2,

C5, and C7). You

will only hear a

click every few

seconds if C5 is in

the circuit.

Project 174

More Capacitors in Parallel

Project 173

Capacitors in Parallel (III)

-77-

Turn on the right slide switch

(S1). Set the lever on the

adjustable resistor (RV) to each

side and compare the sound

with the left slide switch on or off.

With the lever up, RV is a 200W

resistor. Turning the left switch

off connects this in series with

the 5.1kWresistor (R3), and

has a small effect on the tone.

With the lever down, RV is a

50kWresistor. Turning the left

switch off connects this in

series with the 5.1kWresistor

(R3), and has a big effect on

the tone.

Turn on the right slide switch (S1). Set the

lever on the adjustable resistor (RV) to

each side and compare the sound with the

left slide switch on or off. If there is no

sound when the lever is set all the way up,

adjust it down a little until there is sound.

With the lever up, RV is a 200Wresistor.

Turning the left switch off connects this in

parallel with the 5.1kWresistor (R3), and

has a big effect on the tone.

With the lever down, RV is a 50kWresistor.

Turning the left switch off connects this in

parallel with the 5.1kWresistor (R3), and

has a small effect on the tone.

Pressing any of the green keys now will

change the tone, by connecting resistors

inside the keyboard in parallel with your

R3-RV resistor network.

Project 175

Resistors in Series

Project 176

Resistors in Parallel

Think of resistors as

obstructions to the flow of

electricity. When there is only

one path for electricity and

part of it has a big

obstruction, not much will

flow. When there are several

paths for electricity and one

has a big obstruction, a lot

will flow because most will

flow through the

unobstructed path.

Inside the keyboard module (U26) is an

oscillator circuit that produces separate

tones for the blue and green keys. The

frequency (pitch) of the tone is set using

an internal resistor-capacitor network,

with each key representing a different

resistor value. The green keys can be

adjusted using the tune knob.

The tone of the green keys can also be

changed using external resistors and

capacitors, which is done in many of the

projects.

-78-

Turn on the right slide switch (S1).

There are five resistors (R1, R3, RV,

RV3, and RP), connected in parallel,

that are controlling the current to the

color LED (D8). See which resistor

has the most effect on the LED

brightness, by removing them one at

a time. The resistance of RV and RV3

depends on their setting, so try them

at different settings.

These five resistors are all

connected in parallel, so the

smallest one (R1, 100W),

will have the most effect.

Turn on the slide switch (S1). There are five

resistors (R1, R3, RV, RV3, and RP),

connected in series, that are controlling the

current to the color LED (D8). See which

resistor has the most effect on the LED

brightness, by replacing them with a 3-snap

wire or the red/black jumper wires, one at a

time. The resistance of RV and RV3 depends

on their setting, so try them at different

settings. Note that the photoresistor’s (RP’s)

resistance can be very high if there isn’t bright

light shining on it.

Project 177

Lots of Resistors in

Series

Project 178

Lots of Resistors in

Parallel

These five resistors are all

connected in series, so the

highest value, will have the

most effect.

Swapping the locations of any

parts in the circuit (without

changing the direction of their

“+” side) will not change how

the circuit works. Try it.

-79-

Project 179 Be a Loud Musician

Project 180

Be a Loud Musician (II)

Use the preceding circuit and songs, but press both the blue and

green keys for each note, at the same time. Try this with the blue and

green keys aligned (as per project 2), but also try them at different

TUNE knob settings (so the keys are out of alignment.

It’s Raining, It’s Pouring:

A G E A G E G G E A G E E

It’s rain-ing, it’s pour-ing, Rain-y days aren’t bor-ing. We

F F D D F F D D G F E D E C

like to jump, we like to splash, Let’s hope it rains till mor-ning.

Jingle Bells

E E E E E E E G C D E–

Jin-gle bells, jin-gle bells, Jin-gle all the way,

F F F F F E E E E C G F D C–

Oh what fun it is to ride in a one horse o-pen sleigh.

London Bridge is Falling Down

G A G F E F G D E F E F G

Lon-don Bridge is fal-ling down, Fal-ling down, fal-ling down.

G A G F E F G D– G– E C–

Lon-don Bridge is fal-ling down, My fair la-dy.

If You’re happy and You Know It

C C F F F F F F E F G–

If your’re hap-py and you know it, clap your hands.

C C G G G G G G F G A–

If your’re hap-py and you know it, clap your hands.

A A A# A# A# A# D D A# A# A A A G F F–

If you’re hap-py and you know it, And you real-ly want to show it,

A# A# G G G F E C D E F–

If your’re hap-py and you know it, clap your hands.

A Tisket, A Tasket

E G E F G E G C E A G E E

A tis-ket a tas-ket, A green and yel-low bas-ket

F F D D F F D D G F E D E C–

I wrote a let-ter to my love and on the way I dropped it.

Let’s play some more songs. Build the circuit shown here (it is similar

to the project 1 circuit, but louder), and turn on the slide switch (S1).

For best song quality, align the blue and green keys together: Turn the

TUNE knob while pressing the blue C key and the green C key at the

same time. Slowly turn the knob across its entire range, and see how

the sound varies. At most TUNE knob positions you will notice

separate tones from the blue and green keys, but there will be a knob

position where the blue and green tones blend together and seem like

a single musical note - this is the best TUNE setting to play songs with.

The blue and green keys are now aligned together.

To play a song, just press the key corresponding with the letter shown.

If there is a “–” after a letter, press the key longer than usual.

-80-

Some songs have

been modified to

make them easier

to play on your

keyboard.

Build the circuit and turn on the right switch (S1). Press

one key in a series of long and short bursts with pauses

in between, and use Morse Code to send secret

messages to your friends.

You can use the difference in pitch between keys to send

messages to different people. For example, sending

Morse Code with the blue C key can mean that the

message is for one friend, using the green C key can

mean it’s for someone else, the green B key can be

someone else. Turn on the left slide switch makes the

pitch of the green keys much different, so can be used to

identify messages for additional friends.

Morse Code: The forerunner of today’s telephone system

was the telegraph, which was widely used in the latter half

of the 19th century. It only had two states - on or off (that is,

transmitting or not transmitting), and could not send the

range of frequencies contained in human voices or music. A

code was developed to send information over long distances

using this system and a sequence of dots and dashes (short

or long transmit bursts). It was named Morse Code after its

inventor. It was also used extensively in the early days of

radio communications, though it isn’t in wide use today. It is

sometimes referred to in Hollywood movies, especially

Westerns. Modern fiber optics communications systems

send data across the country using similar coding systems,

but at much higher speeds. Indian tribes sometimes used

smoke signals to send messages.

MORSE CODE

A . _

B _ . . .

C _ . _ .

D _ . .

E .

F . . _ .

G _ _ .

H . . . .

I . .

J . _ _ _

K _ . _

L . _ . .

M _ _

N _ .

O _ _ _

P . _ _ .

Q _ _ . _

R . _ .

S . . .

T _

U . . _

V . . . _

W . _ _

X _ . . _

Y _ . _ _

Z _ _ . .

Period

. _ . _ . _

Comma

_ _ . . _ _

Question . . _ _ . .

1 . _ _ _ _

2 . . _ _ _

3 . . . _ _

4 . . . . _

5 . . . . .

6 _ . . . .

7 _ _ . . .

8 _ _ _ . .

9 _ _ _ _ .

0 _ _ _ _ _

Project 181 Morse Code

-81-

Transistor Audio

Amplifier

Build the circuit with the speaker (SP2) connected

using the red & black jumper wires. Set the

adjustable resistor (RV) to mid-range, and turn on

the slide switch (S1). Hold the speaker next to your

ear and blow into the microphone (X1), or talk

directly into it with your mouth close to it.

This circuit amplifies your voice and plays it on the

speaker. It should be easy to hear the blowing, but it

may be difficult to understand your voice, because

there isn’t enough amplification and there will be

some distortion. Also, the sound from the speaker

may not be as loud as hearing your voice directly.

If you have headphones (not included),

then modify the preceding circuit to match

this one, and connect your headphones to

the audio jack (JA). Set the adjustable

resistor (RV) to mid-range, and set the

500kWadjustable resistor (RV3) for most

comfortable sound level (turn to the left for

higher volume, most of RV3’s range will be

very low volume). Turn on the slide switch

(S1). Blow into the microphone (X1), or talk

directly into it with your mouth close to it.

The sound may not be very loud.

Headphones

(not included)

WARNING: Headphones performance varies, so use caution. Start with

low volume, then carefully increase to a comfortable level. Permanent

hearing loss may result from long-term exposure to sound at high volumes.

Project 182

Transistor Audio

Amplifier (II)

Project 183

With headphones it may be

easier to recognize the

difference between the

circuit sound and hearing

your voice directly, than it

had been with the speaker.

-82-

Method A (easy): Spread some water on the table into

puddles of different shapes, perhaps like the ones

shown here. Touch the jumper wires to points at the

ends of the puddles. Small, narrow puddles may not

produce any sound.

Method B (challenging): Use a SHARP pencil (No. 2 lead is best) and draw

shapes, such as the ones here. Draw them on a hard, flat surface. Press hard

and fill in several times until you have a thick, even layer of pencil lead. Touch

the jumper wires to points at the ends of the drawings, then move them across

the drawing to vary the sound. You may get better electrical contact if you wet

the metal with a few drops of water. Wash your hands when finished.

Method C (adult supervision and permission required): Use some double-

sided pencils if available, or VERY CAREFULLY break a pencil in half. Touch

the jumper wires to the black core of the pencil at both ends.

Build the circuit and turn on the switch (S1). Initially set the lever on the

adjustable resistor (RV) to the left, then move it later to vary the range of

sounds that can be produced. Make your parts using either the water

puddles method (A), the drawn parts method (B), or the pencil parts method

(C). Touch the metal in the jumper wires to your parts and listen to the sound.

Long, narrow shapes

have more resistance

than short, wide ones.

The black core of

pencils is graphite,

the same material

used in the resistors.

Next, place the loose ends of the jumper

wires in a cup of water, make sure the

metal parts aren’t touching each other.

The water should change the sound.

The pitch may depend on the amount of

water, so see if adding more water to the

cup changes the sound.

Now add salt to the water and stir to

dissolve it. The sound should have

higher pitch now, since

salt water has less

resistance than plain

water.

Don’t drink any water used

here.

Project 185

Color Touch Light

Build the circuit. It doesn’t do anything,

and may appear to be missing

something. It is missing something,

and that something is you.

Touch points A & B with your fingers.

The color LED (D8) may be lit. If isn’t,

then you are not making a good

enough electrical connection with the

metal. Try pressing harder on the

snaps, or wet your fingers with water

or saliva. The LED should be on now.

If it isn’t very bright, then try going into

a dimly lit room.

Make Your Own Parts

Project 184

-83-

Project 186

Test Your Hearing

This project requires a smart phone with an internet connection, so you

can download a free app. Find and download a “function generator” app

that can generate sine and square signals. Visit the Snap Circuits®Sound

product page at http://www.elenco.com/downloads/scs185/ to find a few

suggestions.

Set the app for “Sine” function (for a

single tone), start it, and vary the

frequency across the available range.

You can listen to the sound directly on

your smart phone, or use the circuit in

project 60. Set the volume control on

your smart phone (and using RV, if

you are using project 60) so that the

sound is at a comfortable level for

middle frequencies.

See what range of frequency you can

hear. Notice that the sound is loud at

middle frequencies, but low (or no

sound at all) at low or high frequency.

There are two reasons for this:

1. Your hearing ability depends on frequency. Most people can hear

frequencies in the range of 20 Hz to 20,000 Hz, but much better in the

middle of this range than at the low or high ends of it. As you get older

you don’t hear higher frequencies as well, so use the same circuit to

see what range of frequency your grandparents can hear.

2. Your speaker’s ability to produce sound depends on frequency, and it

may not perform as well at low or high frequency. Speakers are only

designed to produce sound in the range that we can hear.

Part B: set the frequency on the function generator app to just below what

you can hear, then change the function from “Sine” to “Square” function

(for a tone with lots of overtones). You should be able to hear it now,

because a signal with overtones has some energy at higher frequencies,

which should be within your hearing range.

This project requires a smart phone with an internet connection, so you

can download a free app. Find and download an “oscilloscope” app that

lets your smart phone act as an oscilloscope. Visit the Snap Circuits®

Sound product page at http://www.elenco.com/downloads/scs185/ to find

a few suggestions.

An oscilloscope is an instrument that engineers use to actually look at

electrical signals. Constant tones are especially interesting to look at,

because they are repetitive and actually look like a wave.

Start the app and talk

into the smart phone’s

microphone, and watch

your voice on the screen.

Try making a single tone

at different frequencies,

or whistling, or snapping

your fingers.

Next, use the one of the keyboard (U26) circuits such as projects 1 or 25-

26. Make sound with the keyboard and see what it looks like.

Try an echo circuit such as project 29, and see what an echo looks like.

-84-

Project 187

See the Sound

This project requires a smart phone with an internet connection, so you can

download a free app. Find and download a “spectrum analyzer” app that

lets your smart phone view the frequency spectrum of a signal. Visit the

Snap Circuits®Sound product page at

http://www.elenco.com/downloads/scs185/ to find a few suggestions.

A spectrum analyzer is an instrument that engineers use to look at the

frequency content of electrical signals, and shows which frequencies have

the most energy. A pure tone will have all its energy at a single frequency,

while a tone with overtones will have the most energy at the main tone,

but also have energy at multiples of the main tone. A complex sound will

have its energy spread across many frequencies.

Spectrum analyzers usually show data as a chart of energy content versus

frequency. Energy is usually shown in dB (decibels), a logarithmic

measurement, so the strongest frequencies have much more energy than

the weak ones shown. There is always a “noise floor” of background noise,

which can make weak signals difficult to observe.

Start the app and talk into the smart phone’s microphone, and watch the

frequency content of your voice on the screen. Try making a single tone

at different frequencies, or whistling.

Next, use the one of the keyboard (U26) circuits such as projects 1, 6, or 25-26.

Make sound with the keyboard and see what its frequency content looks like.

See the Spectrum

Project 188

Project #B1

See the Sound

This circuit uses the color organ module (U22) from the SCL-175

set. Build the circuit as shown, turn off the left slide switch (S1),

and turn on the right slide switch. Press keys on the keyboard to

make sounds and change the light on the color organ. Turn on the

left slide switch to add optical control, and wave your hand over

the photoresistor to also change the sound and light. If desired,

add one of the SCL-175 LED attachments on the color organ.

BONUS CIRCUIT FOR SNAP CIRCUITS®LIGHT OWNERS

-85-

If you own Snap Circuits®LIGHT (Model SCL-175), then

you may also build this circuit. Do not connect additional

voltage sources from other sets, or you may damage

your parts. Contact Elenco®if you have any questions.

-86-

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Including:

Snap Circuits®Extreme

Model SC-750

• Strobe light

• Transistor AM radio

• Electromagnetism

• Rechargeable battery

Contains over 80 parts

Including:

• Solar cell

• Electromagnet

• Vibration switch

• Computer interface

Snap Circuits®Green

Model SCG-125

Build over 75 projects

Projects relate to electricity in the home and

magnetism and how it is used.

Snaptricity®

Model SCBE-75

Contains over 40 parts

Including:

Meter, electromagnet, motor, lamps, switches,

fan, compass, and electrodes.

Alternative Energy Kit

Build over 125 projects and have loads of fun learning

about environmentally-friendly energy and how the

electricity in your home works. Includes full-color manual

with over 100 pages and separate educational manual.

This educational manual will explain all the forms of

environmentally-friendly energy including: geothermal,

hydrogen fuel cells, wind, solar, tidal, hydro, and others.

Contains over 40 parts.

Snap Rover®

Model SCROV-10

Snap Circuits®Light

Model SCL-175

Have FUN building your own RC Snap Rover®

using the colorful Snap Circuits®parts that

come with this kit. There is no soldering

required as all the parts snap together with

ease. Once completed, you will be able to

navigate your surroundings with the easy-to-

use Snap Rover®remote control.

Contains over 20 projects

and over 30 parts

Build over 175 projects

Including:

Contains over 55 parts

Including:

Strobe light, color organ, infrared detector, color

changing LED, fiber optic cable, and more!

• Fiber Fun

• Dancing Lights

• Follow the Music

• Audio Infrared Detector

SCS-185 SOUND Block Layout

Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER.

Call toll-free (800) 533-2441 or e-mail us at: help@elenco.com. Customer Service • 150 Carpenter Ave.

Wheeling, IL 60090 U.S.A. Note: A complete parts list is on pages 2 and 3 in this manual.

Base grid (11.0” x 7.7”) overlays many parts

SCS 185_Manual 185 Manual

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